pgsql: pg_createsubscriber: Add '--all' option.

pg_createsubscriber: Add '--all' option.

The '--all' option indicates that the tool queries the source server
(publisher) for all databases and creates subscriptions on the target
server (subscriber) for databases with matching names. Without this user
needs to explicitly specify all databases by using -d option for each
database.

This simplifies converting a physical standby to a logical subscriber,
particularly during upgrades.

The options '--database', '--publication', '--subscription', and
'--replication-slot' cannot be used when '--all' is specified.

Author: Shubham Khanna <khannashubham1197@gmail.com>
Reviewed-by: vignesh C <vignesh21@gmail.com>
Reviewed-by: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Reviewed-by: Euler Taveira <euler@eulerto.com>
Reviewed-by: Hayato Kuroda <kuroda.hayato@fujitsu.com>
Reviewed-by: Amit Kapila <amit.kapila16@gmail.com>
Reviewed-by: Peter Smith <smithpb2250@gmail.com>
Reviewed-by: Shlok Kyal <shlok.kyal.oss@gmail.com>
Discussion: https://postgr.es/m/CAHv8RjKhA=_h5vAbozzJ1Opnv=KXYQHQ-fJyaMfqfRqPpnC2bA@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/fb2ea12f42b9453853be043b8ed107e136e1ccb7

Modified Files
--------------
doc/src/sgml/ref/pg_createsubscriber.sgml          |  37 ++++++--
src/bin/pg_basebackup/pg_createsubscriber.c        | 104 ++++++++++++++++++++-
src/bin/pg_basebackup/t/040_pg_createsubscriber.pl |  57 +++++++++++
3 files changed, 187 insertions(+), 11 deletions(-)