Return member objects for guilds oauth2 scope

[muddyfish]

It would be pretty nice if when you request the 'guilds' scope there was a method of retrieving the full member objects in servers the connected bot is in.

This would be useful for a web dashboard so you don't have to cache every member just in case they happen to use a web dashboard and need to fetch individual permissions to see if a user is allowed to interact with certain features.

Whilst this wouldn't remove the need for the GUILD_MEMBERS intent, it could definitely reduce the need for caching full member lists.

Related to #1323.

[advaith1]

/users/@me/guilds already has the user's permissions though 🤔

[muddyfish]

It doesn't have the users roles, so you can't calculate per channel permissions

[advaith1]

that's true, but you would need to fetch the channels too; why not just use a bot and fetch the member?

[Skye-31]

Perhaps not adding the entire member object, but just including an array of role snowflakes they have would be helpful.

[muddyfish]

Personally I'd be fine keeping channels cached as there are significantly fewer of them than members.
I'm mostly trying to avoid sending off a maximum of 100 requests for roles whenever someone looks at my dashboard.

At this point, it would be also be helpful to just have a boolean specifying if my bot is also in the server so I don't have to iterate through them all to find matches, which might be possible given I've heard mutual servers with bots might be coming on the user side.