Image and SDK package jobs call the same package script just with
different arguments. Instead of having two job classes package_release
and package_sdk for these two tasks, merge them into the base class
package and make the differences configurable via a variable
PACKAGE_TYPE.
Instead of hard-coding the rules for manual builds in each actual job,
conditionally add this to the buildbase class and add a variable
MANUAL_BUILD to the according jobs.
Image and SDK builds share a lot of similar code. Instead of having two
job classes build_yocto_image and build_yocto_sdk for these two
tasks, merge them into the base class build_yocto and make the
differences configurable via a variable.
The dump_install_command part of the script, which was not executed
for SDK builds, is always present now, but it's only executed if the
INSTALLSCRIPT variable is set, which is not the case for SDK builds.
The collect_srcrevs part of the script is executed in all cases. It
was not part of the SDK build before, but it's not less relevant there.
Yocto build: make main artifacts path configurable
Instead of specifying all possible artifacts paths and abusing the fact
that GitLab ignores non-existing paths during artifact upload, implement
a cleaner solution with a configurable path.
