Specify absolute templates submodule path

This way people who want to contribute changes from forks don't experience a failing pipeline without forking the templates repo as well.

@jandt-desy Is this fine from your side. This is required to fix the pipeline in !504 (closed) for instance.

added Progress::4_Can review label

requested review from @jandt-desy

assigned to @frust45

changed title from Specify templates submodule path absolute to Specify absolute templates submodule path

@frust45 fine for me. I don't quite get why this one works and that one didn't but I cannot dig into that soon, so please merge.

approved this merge request

resolved all threads

merged

mentioned in commit 0bc1124b

mentioned in issue #313 (closed)