pgsql: pg_createsubscriber: Introduce module-specific logging functions

pg_createsubscriber: Introduce module-specific logging functions.

Replace generic pg_log_* calls with report_createsub_log() and
report_createsub_fatal(). This refactor provides the necessary
infrastructure to support logging to external files via the -l option.

These new functions enable the utility to route messages to both the
terminal and a log file based on the logging configuration and verbosity
levels provided by the user.

Author: Hayato Kuroda <kuroda(dot)hayato(at)fujitsu(dot)com>
Author: Gyan Sreejith <gyan(dot)sreejith(at)gmail(dot)com>
Reviewed-by: shveta malik <shveta(dot)malik(at)gmail(dot)com>
Reviewed-by: Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
Discussion: https://postgr.es/m/CAEqnbaUthOQARV1dscGvB_EsqC-YfxiM6rWkVDHc+G+f4oSUHw@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/d6628a5ea0a56b62eb3feaa8d8210ce76e9afc2c

Modified Files
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src/bin/pg_basebackup/pg_createsubscriber.c | 749 ++++++++++++++++++----------
1 file changed, 477 insertions(+), 272 deletions(-)