Resolve "Make project-template usable by CSO"

Merge Request Description

Creates a trigger pipeline, which first discovers the os-type used in the given branch. The appropriate pipeline will then be triggered.

This allows us to no longer need to know the parent image type to get the correct pipeline to run.

Merge Request Info

Risk

Would break all pipelines if there were an uncaught issue

Rollback Plan

Revert MR

Testing

In Mario

• alpine - development branch
• openJDK11 - master branch
• Scratch - master branch

Closes #724 (closed)