dev-db/postgresql: Version Bumps and more
Bump versions to: 12.3, 11.8, 10.13, 9.6.18, 9.5.22
The 9.4 series is now EOL, and will be masked for removal.
Additionally:
- Dropped L10N since it doesn't actually do anything
- Removed the underscore in a use flag to comply with policy:
pg_legacytimestamp is now pg-legacytimestamp
- Removed outdated and nonexistent blockers
- Added "server" use flag to help clean up some harmless notices in gentoo-ci
- Migrated from user.eclass to GLEP 81
Closes: https://bugs.gentoo.org/723082
Package-Manager: Portage-2.3.99, Repoman-2.3.22
Signed-off-by: Aaron W. Swenson <titanofold@gentoo.org>