Before only the ID was used but the CI_OPEN_MERGE_REQUESTS variable has
the complete path.

The project name is matched with the predefined gitlab var CI_PROJECT_NAME,
which uses lower case.

Added default source revision file name to common.py.
Modified the integration_into_manifest function to set the
corresponding subproject hash in the SRCREV.conf file if the
repository is not found in the default.xml file. The
merge_into_manifest function now works even if the names of
the master branches in the manifest and in the project
repository are different.

BCS 746-000016

The function used to rely on the given merge request object without
checking its current state. If the given object was not in one of the
"unchecked" states, it returned immediately. The state, however, could
have changed between its last query and the call of this function, so
it now checks the state first before deciding anything.

Unfortunately, GitLab still interpreted three of the four dashes as
start and end of YAML syntax, so we go back to two dashes.

The former "---" was still rendered as YAML syntax by GitLab in some
cases.

Restore the "---" separator which was removed in a previous commit. The
description simply must not start with this separator. If we include it
only in between the blocks, all instances are rendered as a horizontal
line, which makes the MR description more readable. Include a helper
function for this purpose, which extracts the message body from a commit
message.

GitLab renders "---" as a horizontal line or as a frame. We do not want
this, so replace it with "--".

The jobs in the deploy stage have to be triggered manually in GitLab.
There is one deploy job for each project which uses the gitlab-ci
scripts as a submodule, so that the deployment can be performed step by
step.

If executed within MR context, an integration MR is created and left
open. The user can extend this integration MR, e.g. if CI scripts have
been renamed, changed command line arguments or other changes requiring
updates of the correspronding .gitlab-ci.yml file. Subsequent runs of
this job will re-create the integration branch, so manual changes are
lost in this case.

If executed on the master branch (i.e. after the source MR has been
merged), the job does exactly the same, plus the integration MR will be
automatically merged. If this fails, the job will fail as well.

* Add retrigger_mr_pipeline_py script
* Move get_merge_request() function to separate file and make it return all
  available pipelines instead of just one
* Add helper script for parsing projects from manifest file