Option for custom logic for checking permissions

[ulhaq]

This could be useful in cases where we don't want to retrieve the permissions from the database on every request.
For example, when permissions are stored and retrieved from an access token.

[PaolaRuby]

@freekmurze @Nielsvanpach @drbyte is this package abandoned?

[freekmurze]

@ulhaq Could you add an entry in the docs with a clear example on why you would use this option?

@PaolaRuby no

[PaolaRuby]

@freekmurze docs added

[freekmurze]

Thank you!