Display advanced deprecation notice for postgres 12

Start notifying sysadmins that PG12 is deprecated, and support will be removed in GitLab 16.0

Updates similar to !4918 (merged) and !4706 (merged)

• Update remote check in files/gitlab-cookbooks/gitlab/recipes/database_migrations.rb to warn about PG versions less than 13
• Update deprecation check in files/gitlab-cookbooks/postgresql/recipes/bin.rb
• Update deprecation message, and turn on the message in files/gitlab-ctl-commands/upgrade.rb
• Update the deprecation message used in in files/gitlab-ctl-commands/pg-upgrade.rb