pgsql: Further cleanup for directory creation on pg_dump/pg_dumpall

Further cleanup for directory creation on pg_dump/pg_dumpall

Instead of two separate (and different) implementations, refactor to use
a single common routine.

Along the way, remove use of a hardcoded file permissions constant in
favor of the common project setting for directory creation.

Author: Mahendra Singh Thalor <mahi6run@gmail.com>

Discussion: /messages/by-id/CAKYtNApihL8X1h7XO-zOjznc8Ca66Aevgvhc9zOTh6DBh2iaeA@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/4170298b6ecff7ce697b81e13d9a81e3b825798c

Modified Files
--------------
src/bin/pg_dump/dumputils.c | 36 ++++++++++++++++++++++++++++++++
src/bin/pg_dump/dumputils.h | 1 +
src/bin/pg_dump/pg_backup_directory.c | 36 ++------------------------------
src/bin/pg_dump/pg_dumpall.c | 39 +----------------------------------
4 files changed, 40 insertions(+), 72 deletions(-)