Add a pattern recognition sandbox for EF tracking and other users
Replaces !67512 (closed).
In this MR, we add a lightweight wrapper to plug under-development pattern recognition logic into the Phase-2 ATLAS/ACTS tracking chain and interface them to downstream reco and validation using IDPVM. Intended mainly for EF tracking developments, but open to other uses. Minimizes exposure of developers to athena / ACTS technicalities.
The package was discussed in the ACTS/ITk integration meeting. Since then, the classes have been renamed and merged into the general Acts tracking namespace to signify their wider potential user base.
Also add a CI test that tests the basic functionality of this chain.