include submodule CI jobs

The submodules now have their own CI pipelines which is just cleaner. The main .gitlab-ci.yml should include those other pipelines so that no inconsistent build jobs exist.

Definition of Done:

• add pipelines to all submodules
• remove submodule build jobs from .gitlab-ci.yml
• include submodule pipelines
• properly define before_scripts to cd to the correct paths
• test

Hints:

• This issue requires to update submodule references to relatively new versions.