Add get single organization handler

[nayyara-airlangga]

I decided to add a handler to get a single organization by its organization code. This is so that a library user could get the organization they need without needing to get all organizations by themselves (this is done internally in the new handler) and also without having to get the organization they need from the hash map themselves.

An additional side effect from this is that we could also remove Clone trait that would otherwise be needed if we just had the orgs::get_organizations as that would return a hash map and getting a value from a hash map would return a reference instead of the actual value required in the SSOJWTClaims and SSOUser structs. The new handler would move the value out of the hash map, meaning there is no need for cloning.