feat: add global logout to clear all sessions, access tokens, email tokens and password tokens

[SychO9]

Relies on #3587

Changes proposed in this pull request:

• Adds a forum controller that clears the current session and all access tokens, email tokens, and password tokens.
• Adds a security button to link to the security page in the session dropdown.

Screenshot

Necessity

• [ ] Has the problem that is being solved here been clearly explained?
• [ ] If applicable, have various options for solving this problem been considered?
• [ ] For core PRs, does this need to be in core, or could it be in an extension?
• [ ] Are we willing to maintain this for years / potentially forever?

Confirmed

• [ ] Frontend changes: tested on a local Flarum installation.
• [ ] Backend changes: tests are green (run composer test).
• [ ] Core developer confirmed locally this works as intended.
• [ ] Tests have been added, or are not appropriate here.

[luceos]

I wouldn't want to sacrifice an entry in the session dropdown now, the entry on the user settings page imo suffices. Screen space is limited as is, especially on mobile. Thoughts?

[davwheat]

Hmmm that's a good point. I think having it under settings on its own should be fine.

[SychO9]

That's fine by me

[SychO9]

Since this relies on #3587 we'll merge when that's done.