Check for all required signatures for each slice

Follow up on !48124 (merged), to prevent issues like ATR-24595.

Moves the combined/calib signature lists to be class variables instead of instance variables, since these are the same for every menu.

Should print all incorrectly placed chains before breaking on the slice.

I'm not especially fond of the Egamma/Electron/Photon logic needing to be handles specially everywhere but the fact that Signature=Electron/Photon and Slice=Egamma more or less requires it, so I have tried to maintain the slice/signature identification.

For merging after !48414 (merged).