pgsql: Add USER SET parameter values for pg_db_role_setting

Add USER SET parameter values for pg_db_role_setting

The USER SET flag specifies that the variable should be set on behalf of an
ordinary role. That lets ordinary roles set placeholder variables, which
permission requirements are not known yet. Such a value wouldn't be used if
the variable finally appear to require superuser privileges.

The new flags are stored in the pg_db_role_setting.setuser array. Catversion
is bumped.

This commit is inspired by the previous work by Steve Chavez.

Discussion: https://postgr.es/m/CAPpHfdsLd6E--epnGqXENqLP6dLwuNZrPMcNYb3wJ87WR7UBOQ%40mail.gmail.com
Author: Alexander Korotkov, Steve Chavez
Reviewed-by: Pavel Borisov, Steve Chavez

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/096dd80f3ccc103c8e078fca05e6ccfb2071aa91

Modified Files
--------------
doc/src/sgml/catalogs.sgml | 10 ++
doc/src/sgml/ref/alter_database.sgml | 15 +-
doc/src/sgml/ref/alter_role.sgml | 22 ++-
doc/src/sgml/ref/alter_user.sgml | 2 +-
doc/src/sgml/ref/psql-ref.sgml | 7 +
src/backend/catalog/pg_db_role_setting.c | 46 +++++-
src/backend/catalog/pg_proc.c | 1 +
src/backend/commands/functioncmds.c | 4 +-
src/backend/parser/gram.y | 20 +++
src/backend/utils/adt/arrayfuncs.c | 1 +
src/backend/utils/fmgr/fmgr.c | 1 +
src/backend/utils/misc/guc.c | 161 ++++++++++++++++++---
src/backend/utils/misc/guc_funcs.c | 12 +-
src/bin/pg_dump/dumputils.c | 5 +
src/bin/pg_dump/dumputils.h | 1 +
src/bin/pg_dump/pg_dump.c | 27 +++-
src/bin/pg_dump/pg_dumpall.c | 12 +-
src/bin/psql/describe.c | 11 +-
src/bin/psql/tab-complete.c | 4 +
src/include/catalog/catversion.h | 2 +-
src/include/catalog/pg_db_role_setting.h | 2 +
src/include/nodes/parsenodes.h | 1 +
src/include/utils/guc.h | 11 +-
src/test/modules/Makefile | 1 +
src/test/modules/meson.build | 1 +
.../modules/test_pg_db_role_setting/.gitignore | 4 +
src/test/modules/test_pg_db_role_setting/Makefile | 29 ++++
.../expected/test_pg_db_role_setting.out | 143 ++++++++++++++++++
.../modules/test_pg_db_role_setting/meson.build | 35 +++++
.../sql/test_pg_db_role_setting.sql | 63 ++++++++
.../test_pg_db_role_setting--1.0.sql | 7 +
.../test_pg_db_role_setting.c | 57 ++++++++
.../test_pg_db_role_setting.control | 7 +
src/test/regress/expected/psql.out | 6 +-
34 files changed, 680 insertions(+), 51 deletions(-)