Use underscore to separate words within variable name.

FNG_INSTALL_URL was defined in build.env only, and in order to use it
during the build we sourced build.env after writing it.
Remove this workaround and define the variable cleanly in the first
place. This removes the intermediate variable FNG_INSTALL_PATH.
Also move the "/artifact" path from JOB_URL to FNG_INSTALL_URL in order
to make the JOB_URL variable name match better.

On every usage of IMAGEPATH, SDKPATH and LICENSESPATH we prepended
BUILDPATH to it. Prepend it directly on definition to prevent
repetition.
Also remove redundant variable IMAGEBASEPATH.

There were three variables set in build.env of which the values are
already known in the environment for all jobs, because they are passed
from the parent pipeline. Use the original variables instead of defining
new ones.

Disable it locally instead, so that
 1. new code additions are always checked, and
 2. we can refactor one function at a time to make the check pass.

This is another check that suggests changes an average developer without
profound Python experience would find hard to understand. Disable it.

See for reference:
https://docs.sourcery.ai/Reference/Python/Default-Rules/for-append-to-extend/

The pkg.py file is no longer deployed by the build process.

See commit
seco-ne/yocto/layers/meta-seconorth-distro@e79e8579

This suggestion aims to reduce code size, but IMO for the expense of
readability for non-python-experts, so we disable it.

See for reference:
https://docs.sourcery.ai/Reference/Python/Default-Rules/use-named-expression/

I don't see any benefit in accepting the refactoring suggestions based
on this rule. IMO it makes the code harder to read, especially for non-
experienced Python developers.

See for reference:
https://docs.sourcery.ai/Reference/Python/Default-Rules/use-next/

See for reference:
https://docs.sourcery.ai/Reference/Python/Default-Rules/raise-specific-error/

The old printf-style string formatting syntax using '%' is not
recommended anymore. See for reference:
https://docs.python.org/3/library/stdtypes.html#printf-style-string-formatting
https://docs.sourcery.ai/Reference/Python/Default-Rules/replace-interpolation-with-fstring/

Python 3.6 introduced f-strings as a better alternative:
https://docs.python.org/3/reference/lexical_analysis.html#f-strings

Consequently switch to this new syntax for all strings.

This stage contains jobs to deploy packaged artifacts to our Azure blob
storage. The required variables `AZURE_STORAGE_ACCOUNT` and
`AZURE_STORAGE_SAS_TOKEN` are stored in the GitLab CI/CD variables.
The storage container `AZURE_CONTAINER_NAME` and artifact path
`AZURE_TARGET_FOLDER` are passed from the parent pipeline.

This adds two jobs to the Yocto pipeline:

 - generate-confluence-page
 - publish-confluence-page

The first one generates a confluence page from a template
(`confluence-page.xml.jinja2`) using information downloaded from all
successful "Deploy FTP" jobs of the same pipeline.

The second one publishes this page in Confluence and displays a link to
the new page. If the page already exists it is overwritten.

The place in Confluence where the new page is published is configurable
via the `CONFLUENCE_SPACE` and `CONFLUENCE_PARENT_ID` variables.

This was accidentally forgotten in the previous commit.

This makes the script more general and open for other future purposes.
The parsing of the YAML content is conditional now, depending on the new
"format" argument.

Instead of mixing dedicated CI test jobs and Yocto build simulation jobs
within one pipeline, use the new multi-build-pipelines architecture to
split them up into separate child pipelines.
This also makes most of the Yocto pipeline code reusable, so that we
don't have to declare all the jobs again in ci-test.

In 438f1e2a we accidentally disabled
caching for the build simulation by moving the cache definition to a job
class. The order of inheritance led to the cache configuration being
overwritten by the one of the "buildbase" class. Change inheritance
order to fix this.

When there are multiple open merge requests for a commit, we currently
take the newest one to determine the integration branch name. This is
not necessarily the correct one, we can have an open merge request with
the commit being part of the commit history while the top commit is a
different one.

Add a check if the commit is the top commit of the merge request in
order to get the correct integration branch name in these cases.

mkstemp() returns a tuple containing an OS-level handle to an open file
(as would be returned by os.open()) and the absolute pathname of that
file, in that order.

Use higher-level function NamedTemporaryFile() instead.

See for reference:
https://docs.sourcery.ai/Reference/Python/Default-Rules/remove-redundant-if/

Move the main part of the action to the if branch.

See for reference:
https://docs.sourcery.ai/Reference/Python/Default-Rules/swap-if-else-branches/

See for reference:
https://docs.sourcery.ai/Reference/Python/Default-Rules/merge-dict-assign/

See for reference:
https://docs.sourcery.ai/Reference/Python/Default-Rules/assign-if-exp/

See for reference:
https://docs.sourcery.ai/Reference/Python/Default-Rules/inline-immediately-returned-variable/

This is the most concise and Pythonic way to create a dictionary.

See for reference:
https://docs.sourcery.ai/Reference/Python/Default-Rules/dict-literal/

A list comprehension can create the list on one line, cutting out the
clutter of declaring an empty list and then appending values.

See for reference:
https://docs.sourcery.ai/Reference/Python/Default-Rules/list-comprehension/

A dictionary comprehension can create the dictionary on one line,
cutting out the clutter of declaring an empty dict and then adding
items.

See for reference:
https://docs.sourcery.ai/Reference/Python/Default-Rules/dict-comprehension/

Something we often do is check whether a list or sequence has elements
before we try and do something with it.

A Pythonic way of doing this is just to use the fact that Python lists
and sequences evaluate to True if they have elements, and False
otherwise.

Doing it this way is a convention, set out in Python's PEP8 style guide.

See for reference:
https://docs.sourcery.ai/Reference/Python/Default-Rules/simplify-len-comparison/

See for reference:
https://docs.sourcery.ai/Reference/Python/Default-Rules/de-morgan/

See for reference:
https://docs.sourcery.ai/Reference/Python/Default-Rules/merge-nested-ifs/