22.0-cleanup-PixelConditionsData

This MR addresses ATLASRECTS-4509 by deleting copy and assignment on the PixelOfflineCalibData object. Additional small cleanup also performed (change bare pointer members to unique_ptr). However while doing this I spotted that a 'resize' on the constants vector was used, when I'm (fairly) sure that reserve was intended. The result of the original code would have doubled the size of the constants vector and placed all zeroes in the first half. Thus, if this is ever used, the output of the 'constants' (on file?) will have changed with this MR. For this reason, a Pixel expert (@stsuno, @tlari , @battagl) should take a look at the code.