PixelITkOffline for 21.9 [ATLITKSW-23]

This MR aims at porting into 21.9 some previous 20.20 developments to retrieve ITk pixel calibration constants to be used for analogue clustering in a release 22-friendly way. This is related to ATLITKSW-23

In particular, a new PixelConditionAlgorithms package is introduced following the release 22 implementation, as well as new data formats specific to ITk in PixelConditionsData.

There are quite a few open points which still need to be sorted out which are discussed below.

FYI: @nstyles @ncalace @npetters @goblirsc @kiabelin @tidreyer @stsuno @sroe