Serbian summit is back in use

[Nemanja Hirsl]

Hello everyone,

The Serbian summit had not been merged since 2020 and now works again :)
I have started using it.

There were a few steps to get here:
- summit_hooks update
- Pology fixes and MRs merged to master. Thanks to Luigi, Karl Ove and
   Johnny.
- Summit merged with current templates for seven catalogs
- All four Serbian variants scattered to trunk

It took more SVN commits than I wanted as some things popped up on the
first scatter and I was (am) still learning the process.

If something looks wrong on the Serbian side, please let me know.

An AI assistant helped with parts of this work (the Pology fixes,
the summit merge, the checks) and catching up with the process.
I reviewed everything before it went out.

Best regards,
Nemanja