pgsql: Add system view pg_ident_file_mappings

Add system view pg_ident_file_mappings

This view is similar to pg_hba_file_rules view, except that it is
associated with the parsing of pg_ident.conf. Similarly to its cousin,
this view is useful to check via SQL if changes planned in pg_ident.conf
would work upon reload or restart, or to diagnose a previous failure.

Bumps catalog version.

Author: Julien Rouhaud
Reviewed-by: Aleksander Alekseev, Michael Paquier
Discussion: https://postgr.es/m/20220223045959.35ipdsvbxcstrhya@jrouhaud

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/a2c84990bea7beadb599d02328190e2a763dcb86

Modified Files
--------------
doc/src/sgml/catalogs.sgml | 107 ++++++++++++++++++++++++++
doc/src/sgml/client-auth.sgml | 10 +++
doc/src/sgml/func.sgml | 5 +-
src/backend/catalog/system_views.sql | 6 ++
src/backend/libpq/hba.c | 31 ++++----
src/backend/utils/adt/hbafuncs.c | 136 +++++++++++++++++++++++++++++++++
src/include/catalog/catversion.h | 2 +-
src/include/catalog/pg_proc.dat | 6 ++
src/include/libpq/hba.h | 1 +
src/test/regress/expected/rules.out | 6 ++
src/test/regress/expected/sysviews.out | 8 ++
src/test/regress/sql/sysviews.sql | 4 +
12 files changed, 305 insertions(+), 17 deletions(-)