FEATURE: Improvements to Authirization system, primarily for ip range
* If available, use the X-Forwarded-For header, rather than the getRemoteAddr() value to get actual IP
* Add PathMappingBooleanOperator which provides a map of access point path to operator (useful for composite
operator, but can be expanded to have further filtering by path)
* isRequestAuth()/setRequestAuth() bean settings added to toggle where to request login when auth fails (default is true)
This is useful for password auth, but not for ip range where access is permenantely blocked.

FIX: Simplify ProxyAccessPoint logic for deciding whether in proxy mode or not.
Allow a ProxyAccessPoint to be just a regular CompositeAccessPoint via the isProxyEnabled()
check, simplifying spring config where both are related.

FIX: Use single header for error reporting:
'X-Archive-Wayback-Runtime-Error' for all error situations including not found, for consistency
Remove any line breaks from the error header as well