Consider instance-based alternative for ControllerLinkBuilder static methods

There are cases when there is no ThreadLocal request context (e.g. SPR-13743, SPR-12800) and other cases where the base path needs to be customized (e.g. SPR-12617). For such use cases consider providing an option to create a ControllerLinkBiulder with a "base" UriComponentsBuilder to use instead of relying on ServletUriComponentsBuilder.fromServletMapping(request) along with instance-based variants of the presently static methods. In effect use of the "current request" becomes optional. This is something we've already done for MvcUriComponentsBuilder in the Spring Framework as an example.

The original request was created in the Spring Framework JIRA as SPR-13743. We can't do anything so I'm "moving" it here.

Start with ControllerLinkBuilder's static methods and compare them with the instance-based approach already used by MvcUriComponentsBuilder in the Spring Framework. Define how a base UriComponentsBuilder replaces the current-request lookup and identify the corresponding instance variants. Done means callers can use a customized base or no request context while existing static behavior remains available.