Unify the template arguments across various template cnfvars

Unify the template arguments across various template cnfvars

There are no obligatory fields as whether any of them are used or
required depends entirly on the cnfvar type/mode for each template.
For instance, AD users may not have password field, GWINLAN providers
may not have local IP, DSL and PPTP providers may not have provider IP,
and protocol forwarding might not have source and destination ports.

It is thus better to unify the function signatures entirely and later
provide some extra facilitation for different cnfvar types/modes.