Support ability to deny resource fetching calls to certain resources for Anonymous users in the mapagent

[jng]

To reduce the attack surface of the MapGuide Web Tier and to prevent unwanted leakage of sensitive connection strings in certain Feature Sources, we should provide the ability for admins to deny the use of resource fetch APIs to anonymous users.

This could be defined as a list of resource ids or resource id prefixes in webconfig.ini that get checked against any resource id of a GETRESOURCE, GETRESOURCEHEADER, GETRESOURCEDATA operation executed in the context of an Anonymous user.