pgsql: Some refactoring of logical/worker.c

Some refactoring of logical/worker.c

This moves the main operations of apply_handle_{insert|update|delete},
that of inserting, updating, deleting a tuple into/from a given
relation, into corresponding
apply_handle_{insert|update|delete}_internal functions. This allows
performing those operations on relations that are not directly the
targets of replication, which is something a later patch will use for
targeting partitioned tables.

Author: Amit Langote <amitlangote09(at)gmail(dot)com>
Reviewed-by: Rafia Sabih <rafia(dot)pghackers(at)gmail(dot)com>
Reviewed-by: Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com>
Discussion: https://www.postgresql.org/message-id/flat/CA+HiwqH=Y85vRK3mOdjEkqFK+E=ST=eQiHdpj43L=_eJMOOznQ(at)mail(dot)gmail(dot)com

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/97ee604d9bcedf0066986521a7ee15e3aa87be34

Modified Files
--------------
src/backend/replication/logical/worker.c | 174 ++++++++++++++++++++-----------
1 file changed, 115 insertions(+), 59 deletions(-)