Egammaperformance24082021

This is the MR of the bug-fixed version of the DQ egamma packages (monitors and webdisplay configuration) for Run3. The branch to be merged has been built on the master version of athena and is to be merged in the master branch. It includes the same content as far as those egamma packages are concerned than the master-DQegamma_07092021_for22.0-mc20 that I required to merge to 22.0-mc20 in a on another merge request.