Add options for skipping access checks and register

[WimdeJager]

This adds two functions to Options:

• SkipRegisterFunction: when this is set and returns true for the given response and request, the current request will not be registered and the access count will not be incremented. This allows skipping certain requests, e.g. it is now possible to skip requests that have a success response. The default is a function that simply returns false.
• SkipAccessCheckFunction: when this is set and returns true, the access check will be skipped. This useful for example to define some IP allowlist (or denylist). The default is again a function that simply returns false.