Rich: CFV RICH channel masking file

This MR provides the channel masking file used in the digitization step
for the RICH CFV version. For more details see #3741

Channel addresses from the new scheme !1968 are used, thus masking with this file is only working after !1968 is merged.

added 2 commits

• 3feecf23 - 1 commit from branch CbmSoft:master
• c4b0323e - add channel masking file for CFV RICH v23a

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Dear @ma.beyer, @s.neuhaus,

you have been identified as code owner of at least one file which was changed with this merge request.

Please check the changes and approve them or request changes.

added CodeOwners label