pgsql: Avoid including commands/dbcommands.h in so many places

Avoid including commands/dbcommands.h in so many places

This has been done historically because of get_database_name (which
since commit cb98e6fb8fd4 belongs in lsyscache.c/h, so let's move it
there) and get_database_oid (which is in the right place, but whose
declaration should appear in pg_database.h rather than dbcommands.h).
Clean this up.

Also, xlogreader.h and stringinfo.h are no longer needed by dbcommands.h
since commit f1fd515b393a, so remove them.

Author: Álvaro Herrera <alvherre(at)kurilemu(dot)de>
Reviewed-by: Bertrand Drouvot <bertranddrouvot(dot)pg(at)gmail(dot)com>
Reviewed-by: Michael Paquier <michael(at)paquier(dot)xyz>
Discussion: https://postgr.es/m/202508191031.5ipojyuaswzt@alvherre.pgsql

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/325fc0ab14d11fc87da594857ffbb6636affe7c0

Modified Files
--------------
contrib/sepgsql/database.c | 1 -
contrib/sepgsql/label.c | 1 -
src/backend/access/heap/vacuumlazy.c | 1 -
src/backend/access/transam/multixact.c | 2 +-
src/backend/access/transam/varsup.c | 2 +-
src/backend/catalog/aclchk.c | 1 -
src/backend/catalog/namespace.c | 1 -
src/backend/catalog/objectaddress.c | 1 -
src/backend/catalog/pg_shdepend.c | 2 +-
src/backend/commands/analyze.c | 1 -
src/backend/commands/comment.c | 2 +-
src/backend/commands/dbcommands.c | 25 +------------------------
src/backend/commands/indexcmds.c | 1 -
src/backend/commands/publicationcmds.c | 1 -
src/backend/commands/schemacmds.c | 2 +-
src/backend/commands/subscriptioncmds.c | 1 -
src/backend/commands/trigger.c | 1 -
src/backend/parser/parse_expr.c | 1 -
src/backend/parser/parse_target.c | 1 -
src/backend/postmaster/autovacuum.c | 1 -
src/backend/replication/logical/slotsync.c | 1 -
src/backend/replication/walsender.c | 2 +-
src/backend/storage/ipc/procarray.c | 2 +-
src/backend/utils/adt/acl.c | 1 -
src/backend/utils/adt/dbsize.c | 2 +-
src/backend/utils/adt/misc.c | 1 -
src/backend/utils/adt/regproc.c | 2 +-
src/backend/utils/adt/xml.c | 1 -
src/backend/utils/cache/lsyscache.c | 27 +++++++++++++++++++++++++++
src/include/catalog/pg_database.h | 1 +
src/include/commands/dbcommands.h | 4 ----
src/include/utils/lsyscache.h | 2 +-
src/test/modules/worker_spi/worker_spi.c | 2 +-
33 files changed, 40 insertions(+), 57 deletions(-)