Handling multiple authentication types

Updates to close out #44. 

* Moving authenticators into CDI providers
* Updating login form tags to handle LDAP login better
* Adding moderator group function to LDAP auth
I don't *think* it would make much difference, but parts of the current implementation would probably be redundant. `LDAPApi` has a private autocloseable class to handle individual method calls, but if the class isn't going to be a singleton that isn't really necessary.