ca: QA module for online reconstruction

In this merge request, a QA module is introduced for the CA tracking in the online reconstruction chain. At the moment one canvas with 5 distributions is defined:

• track_first_theta: polar angle of track in the first hit point
• track_first_phi: azimuthal angle of track in the last hit point
• first_hit_station: active index of tracking station of the first hit
• last_hit_station: active index of tracking station of the last hit
• n_hits: number of hits in a track

@fweig, could you please cross-check the modifications to the online reconstruction chain?