Introduce a Map-based AuthenticationManagerResolver

[jzheaux]

Recently, #6722 introduced a contract for resolving an AuthenticationManager via some context, like a request.

A natural implementation for this would be one that contained a Map<RequestMatcher, AuthenticationManager> and selected the AuthenticationManager from the configured Map.

This aligns with other request-matching API implementations like DelegatingAuthenticationEntryPoint and RequestMatcherDelegatingAccessDeniedHandler.

[clevertension]

i can't find AuthenticationMatcher in the repo, do you mean AuthenticationManager?

[jzheaux]

Good catch, @clevertension. I've updated the description.