Specify permissions for REST params

[andersfylling]

REST requests usually have a set of permissions for usage. However, some might depends on what params you specify.

The idea here is client side permission checking. Each param type must implement PermissionHolder:

type PermissionHolder interface {
	Permissions() PermissionBit
}

Base permission should be hardcoded in the REST method itself. This only deals with permissions related to the parameters.

Cons:

• No way to externally verify if you have required permissions. I'm uncertain if this is a issue, but a quick extraction method (based on func pointer) can be introduced later on.

Pros:

• client side verification, no waste of rate limits and fails quicker