RE: speed up a logical replica setup

Dear Euler, hackers,

I found that some bugs which have been reported by Shlok were not fixed, so
made a top-up patch. 0001 was not changed, and 0002 contains below:

* Add a timeout option for the recovery option, per [1]. The code was basically ported from pg_ctl.c.
* Reject if the target server is not a standby, per [2]
* Raise FATAL error if --subscriber-conninfo specifies non-local server, per [3]
  (not sure it is really needed, so feel free reject the part.)

Feel free to merge parts of 0002 if it looks good to you.
Thanks Shlok to make a part of patch.

[1]: https://www.postgresql.org/message-id/CANhcyEUCt-g4JLQU3Q3ofFk_Vt-Tqh3ZdXoLcpT8fjz9LY_-ww%40mail.gmail.com
[2]: https://www.postgresql.org/message-id/CANhcyEUCt-g4JLQU3Q3ofFk_Vt-Tqh3ZdXoLcpT8fjz9LY_-ww%40mail.gmail.com
[3]:
https://www.postgresql.org/message-id/TY3PR01MB98895BA6C1D72CB8582CACC4F5682%40TY3PR01MB9889.jpnprd01.prod.outlook.com

Best Regards,
Hayato Kuroda
FUJITSU LIMITED