Expose current tag for ease of writing update scripts

[LizzyTrickster]

Original put on discord

Having the current version tag exposed at a publicly viewable address (I.e. Railcraftpack/current) would allow for update notifiers/updates to be made for stuff like MultiMC which can run arbitrary code pre-launch.

Also having the current tag version in the archive will allow for easier checking #28

[Forecaster]

This will also require a special endpoint to request generating the archive (if needed) and pass the file to the script url to the archive in the reply.

It's also going to have to check the patron status if the requester is a patron since it bypasses the regular login.