pgsql: CREATE DATABASE: make LOCALE apply to all collation providers.

CREATE DATABASE: make LOCALE apply to all collation providers.

For CREATE DATABASE, make LOCALE parameter apply regardless of the
provider used. Also affects initdb and createdb --locale arguments.

Previously, LOCALE (and --locale) only affected the database default
collation when using the libc provider.

Discussion: https://postgr.es/m/1a63084d-221e-4075-619e-6b3e590f673e@enterprisedb.com
Reviewed-by: Peter Eisentraut

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/a14e75eb0b6a73821e0d66c0d407372ec8376105

Modified Files
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doc/src/sgml/ref/create_collation.sgml | 23 +++++++----
doc/src/sgml/ref/create_database.sgml | 57 ++++++++++++++++++++------
doc/src/sgml/ref/createdb.sgml | 5 ++-
doc/src/sgml/ref/initdb.sgml | 7 ++--
src/backend/commands/collationcmds.c | 2 +-
src/backend/commands/dbcommands.c | 17 +++++---
src/bin/initdb/initdb.c | 10 ++++-
src/bin/initdb/t/001_initdb.pl | 11 +++++
src/bin/scripts/createdb.c | 13 +++---
src/bin/scripts/t/020_createdb.pl | 15 +++++--
src/test/icu/t/010_database.pl | 33 +++++++++++----
src/test/regress/expected/collate.icu.utf8.out | 22 +++++-----
12 files changed, 155 insertions(+), 60 deletions(-)