There's a merged pull request on the void-packages repository

openttd: packs in separate packages
https://github.com/void-linux/void-packages/pull/53017

Description:
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#### Testing the changes
- I tested the changes in this PR: **YES**
#### Local build testing
- I built this PR locally for my native architecture, amd64-glibc


~~I've moved resource packs behind vopts, as they are not obligatory to run OpenTTD.~~
Resource packs have been moved to separate packages.
Also I provided option to build only dedicated server.
Furthermore I've disabled tests that required resource packs to be present during testing.