Merged charm-helpers into cleanups.
Merged postgresql into charm-helpers.
Let extra_packages be changed after install
Break out package installation
Merged postgresql into charm-helpers.
Merged charm-helpers into cleanups.
Install explicit PG version packages, rather than the "stable version" metapackages. This avoids some issues with charm-helpers filter_installed_packages not filtering as expected, and will be needed in any case to support multiple PG versions again
Fix typo and improve config item description
[stub] filter_installed_packages was not filtering metapackages, so charm was failing if the postgresql package was already installed. Fix this by using the explicit PostgreSQL version, which will also be needed to reenable multiple PG version support.
[stub] Typo in the config.yaml, and improved the description.