Improve Event Building with EUDAQ2 EventLoader

Closes #60 and #55

See merge request !145

EventLoaderATLASpix: updated README, adding description of new parameter 'buffer_depth' + extended example usage

EventLoaderATLASpix: reviving + m_detector->timingOffset() for pixel timestamp which got lost in the renovation works

Skipping detectors with role 'aux' in AlignmentTrackChi2 module

See merge request corryvreckan/corryvreckan!166

EventLoaderATLASpix: moved block of breaking while when hitting eof and buffer is empty to the top of the while loop

EventLoaderATLASpix: more precise inline comment + explicitely set eof_reached=false in initialize()

Rewritten Clipboard & FileReader/Writer Modules

See merge request corryvreckan/corryvreckan!155

EventLoaderATLASpix: removed more old unused variables: oldpos, old_readout_ts, old_fpga_ts, busy_readout_ts

EventLoaderATLASpix: removed 'finalise()' function which is not needed anymore + related unused variables

EventLoaderATLASpix: moved masking pixels a bit earlier and recovered correct filling of pixel ToT BEFORE correction histogram

EventLoaderATLASpix: moving all per-pixel histograms into 'read_caribou_data' to avoid another loop over pixels vector

EventLoaderATLASpix: updated doxygen description for 'read_caribou_data' and remove old commented line

EventLoaderATLASpix: 'read_caribou_data()' now returns false when reaching end-of-file and true otherwise, adjust logic in run() accordingly

EventLoaderATLASpix: removed block in initialise() which does the 'skip before T0' which is now done in 'read_caribou_data()' as well

EventLoaderATLASpix: copying over code block from ATLASpix Raw Decoder in EUDAQ2 and adjusting variable names