Update CI to LCG_98python3

This MR renovates the CI by

• updating to the latest SFT LCG release allpix-squared/allpix-squared!378 (merged)
• cleaning up the YML definition
• moving to a Direct Acyclic Graph running of the pipeline allpix-squared/allpix-squared!368 (merged)
• adding code that exposes testing results to GitLab allpix-squared/allpix-squared!399 (merged)
• updates the way, Clang Format and Clang Tidy are found and used

All these changes are ported from the Allpix Squared repository.