add support for user installation

[xhyrom]

https://discord.com/developers/docs/tutorials/developing-a-user-installable-app#developing-a-userinstallable-app

[mattfbacon]

I don't really understand the purpose of that compared to the normal installation method with the oauth link

[xhyrom]

I don't really understand the purpose of that compared to the normal installation method with the oauth link

It allows you to use the application commands from your account without having the bot in the server.

[mattfbacon]

Hmm, if that is only slash commands then I don't see much point because render and ast only work as normal commands due to code blocks.