Users and NKey users will now have the option to specify a list
of allowed connection types.

This will allow for instance a certain user to be allowed to
connect as a standard NATS client, but not as Websocket, or
vice-versa.

This also fixes the websocket auth override. Indeed, with
the original behavior, the websocket users would have been bound
to $G, which would not work when there are accounts defined, since
when that is the case, no app can connect/bind to $G account.

Signed-off-by: Ivan Kozlovic <ivan@synadia.com>

Signed-off-by: Ivan Kozlovic <ivan@synadia.com>

Signed-off-by: Ivan Kozlovic <ivan@synadia.com>

We were doing option validation from options parsing, but added
it also for Users/NKeyUsers options.

Signed-off-by: Ivan Kozlovic <ivan@synadia.com>