Deprecate openSUSE 15.3 packages

openSUSE Leap 15.3 had its EOL on December 31 2022. In 15.7 we introduced supported OpenSUSE 15.4 packages.

We should:

• Add deprecation changelogs for the OpenSUSE 15.3 package gitlab!109028 (merged)
• Add deprecation to the omnibus package !6626 (merged)