docs: added release build documentation

[frankkopp]

Summary of Changes

Short docu on how releases are done.

Discord username (if different from GitHub): cdr_maverick

[FoxtrotSierra6829]

Tbh I don't think this belongs into the main Readme.md as this is information only for maintainers of the unforked repo.

[frankkopp]

Tbh I don't think this belongs into the main Readme.md as this is information only for maintainers of the unforked repo.

Make a suggestion where to put this. It should be somewhere - it me ages to figure it out again - if you are not doing this daily it is easily forgotten.

[FoxtrotSierra6829]

https://devops.flybywiresim.com/ seems like the best place to me. If necessary, link back in this repo

[frankkopp]

I meant on this repo of course - doesn't make sense to not have it here.
We can in addition to here put it somewhere else.

[frankkopp]

Changed the location, added a docs folder (similar to the aircraft repo) and added a note that this is only relevant for maintainers.

[FoxtrotSierra6829]

Link there in the readme if you really want to. I don't see a reason to put it into this repo as it's really only relevant for maintainers. We wouldn't put how to release a new stable version of our aircraft into the readme of the aircraft repo either, would we? Additionally, writing things twice will result in discrepancies.