Racetime.gg integration

[jeremysmitherman]

Problem description

Adding this integration would allow Opensplit users to synchronize race timers with other players.

Proposed solution

Add an integration to Racetime.gg and save the pertinent configurations in the splitfile.

Alternatives considered

No response

Additional context

No response

[1nf3rna]

https://github.com/1nf3rna/opensplit-racetimegg

Created client. I have tested everything up to joining and running a race.