pgsql: Support invalidating replication slots due to horizon and wal_le

Support invalidating replication slots due to horizon and wal_level

Needed for logical decoding on a standby. Slots need to be invalidated because
of the horizon if rows required for logical decoding are removed. If the
primary's wal_level is lowered from 'logical', logical slots on the standby
need to be invalidated.

The new invalidation methods will be used in a subsequent commit.

Logical slots that have been invalidated can be identified via the new
pg_replication_slots.conflicting column.

See 6af1793954e for an overall design of logical decoding on a standby.

Bumps catversion for the addition of the new pg_replication_slots column.

Author: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com>
Author: Andres Freund <andres@anarazel.de>
Author: Amit Khandekar <amitdkhan.pg@gmail.com> (in an older version)
Reviewed-by: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Reviewed-by: Fabrízio de Royes Mello <fabriziomello@gmail.com>
Reviewed-by: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Reviewed-by: Amit Kapila <amit.kapila16@gmail.com>
Reviewed-by: Melanie Plageman <melanieplageman@gmail.com>
Reviewed-by: Alvaro Herrera <alvherre@alvh.no-ip.org>
Discussion: https://postgr.es/m/20230407075009.igg7be27ha2htkbt@awork3.anarazel.de

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/be87200efd9308ccfe217ce8828f316e93e370da

Modified Files
--------------
doc/src/sgml/system-views.sgml            |  10 ++
src/backend/access/transam/xlog.c         |   8 +-
src/backend/catalog/system_views.sql      |   3 +-
src/backend/replication/logical/logical.c |   7 ++
src/backend/replication/slot.c            | 151 +++++++++++++++++++++++++-----
src/backend/replication/slotfuncs.c       |  12 ++-
src/include/catalog/catversion.h          |   2 +-
src/include/catalog/pg_proc.dat           |   6 +-
src/include/replication/slot.h            |   9 +-
src/test/regress/expected/rules.out       |   5 +-
10 files changed, 176 insertions(+), 37 deletions(-)