Add a higher level abstraction of creating and syncing commands to a specific guild about tanjun

[FasterSpeeding]

This sounds a bit unnecessary imo; declaring commands per-guild was mostly just a debug/dev feature which doesn't make sense at scale and all you need to set the commands on multiple guilds right now is something along the lines of

commands = [...get_commands...]

await asyncio.gather(*(client.declare_application_commands(commands, command_ids={}, guild=guild) for guild in guilds)) 

And that'll handle checking if they've match the already declared commands per-guild unless you also pass force=True.

If you're looking for a way to get specific groups of commands other than global vs non-global then you might be asking for this maybe-TODO which has been sat around for quite a while https://github.com/FasterSpeeding/Tanjun/projects/1#card-73913473.

[GoogleGenius]

I don't remember if I opened this before backend v2 was released or not but yeah, this is probably unnecessary anyway.