Enable direct URI - remote_authority checking

[AnotherDaniel]

Currently, the Uri type comes with a is_remote_authority() method, which takes another Uri as a parameter and compares whether the own vs the other Uri-authority are identical, ie whether the other Uri is local or remote.

To facilitate the case where I directly have an authority string, which I want to compare to a Uri to check for localness/remoteness, we add a Uri method that directly accepts an authority string and performs this check.
This avoids that users in such cases have to artificially construct a Uri from their authority, just so they can use the is_remote_authority() method.