Command-line fixes

[tailhook]

Fixes #1029, #1030

I've left configure as is, but if we want to make it a form similar to other (verb-noun) they should have been insert-config/reset-config/set-config, which I'm not sure are good. Anyway, current configure is good for discoverability.

[elprans]

Please adjust the documentation accordingly.

[tailhook]

Right, sorry. Also, i've just noticed:

  -P, --postgres-dsn TEXT         DSN of a remote Postgres cluster, if using
  -I, --bind-address TEXT         IP address to listen on
  -P, --port INTEGER              port to listen on

(not sure why click doesn't check for that!)
Which -P is right here? I would probably drop short alias for --postgres-dsn at all, I don't see a reason for it to be short (so we keep symmetry in client and server, an also both -I and -P are upper case).

[tailhook]

Updated docs and also dropped -P alias for --postgres-dsn. Let me know if you think it's needed.

[1st1]

I would probably drop short alias for --postgres-dsn

+1. We should only use one letter aliases for commonly used parameters anyways.

[1st1]

(not sure why click doesn't check for that!)

That's quite scary actually.

[elprans]

LGTM.