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

gerbera: runit service fixes
https://github.com/void-linux/void-packages/pull/37903

Description:
#### Testing the changes
- I tested the changes in this PR: **briefly**

The `runit` service was missing `exec` and it did not generate a default config. Combined with the fact that there was no `log` service, it was a little inconvenient to get running.

I left the commits separate for now, but the should probably squashed before merge. 

@crater2150 @octeep