pgsql: Add min() and max() aggregate support for uuid.

Add min() and max() aggregate support for uuid.

The uuid type already has a full set of comparison operators and a
btree operator class, so it is totally ordered. min() and max() were
the only common aggregates missing for it. Add the uuid_larger() and
uuid_smaller() support functions and register the min(uuid) and
max(uuid) aggregates that use them.

uuid values are compared lexicographically over their 128 bits. For
UUIDv7, whose most significant bits encode a Unix timestamp, this
coincides with chronological order, so min() and max() return the
oldest and newest values.

Bump catalog version.

Author: Tristan Partin <tristan(at)partin(dot)io>
Reviewed-by: Bharath Rupireddy <bharath(dot)rupireddyforpostgres(at)gmail(dot)com>
Reviewed-by: Zsolt Parragi <zsolt(dot)parragi(at)percona(dot)com>
Reviewed-by: Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com>
Discussion: https://postgr.es/m/DJGML0T9FCDV.3VA29JLODXEHZ@partin.io

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/2e606d75c0bf9c867b51ad228eae384a9d1de21a

Modified Files
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doc/src/sgml/datatype.sgml | 4 ++++
doc/src/sgml/func/func-aggregate.sgml | 6 ++++--
src/backend/utils/adt/uuid.c | 18 ++++++++++++++++++
src/include/catalog/catversion.h | 2 +-
src/include/catalog/pg_aggregate.dat | 6 ++++++
src/include/catalog/pg_proc.dat | 12 ++++++++++++
src/test/regress/expected/opr_sanity.out | 2 ++
src/test/regress/expected/uuid.out | 7 +++++++
src/test/regress/sql/uuid.sql | 3 +++
9 files changed, 57 insertions(+), 3 deletions(-)