allow /profile or implement a similar endpoint for bots

[VelvetToroyashi]

Right now, the /profile endpoint is unavailable to bots (or, at the very least locked behind OAuth) and that's fine. It makes sense, but /profile contains the ability to pass a very useful query string, that is ?with_mutual_guilds=true.

As it says on the tin, this allows people to see their mutual guilds with someone else if any. Though, as previously stated, this is unavailable to bots under normal circumstances. But this comes in very useful in any situation where the need to see mutual guilds is critical.

Examples of this are for modmail bots. If you use some centrally hosted (that is, a version that a server isn't selfhosting) modmail bot, the bot has two options when it receives a DM:

• Check every guild to see if there's > 1 shared guild (computationally expensive, but very straight forward)
• Prompt the user to click on an OAuth link (which could be a malicious link for all the user knows) and check the guilds provided by the guilds scope

I'd wager most larger bots go with the latter option as it scales better, but I still feel like this is something that should at least be brought up to someone's attention. There's also various other reasons needing to see mutual guilds is important, especially without the need for OAuth

Take Beemo for example, an AI anti-raid bot that has the capability of eradicating raiders from shared servers (that are configured to auto-ban).

[SinisterRectus]

See #3251

[VelvetToroyashi]

Odd. GitHub bad I guess. Didn't see that one before making this.