Adding support for Trilio 4.1 includes the following changes:
* Add Trilio_properties config property to enables templates to distinguish
between 4.0 and 4.1 release.
* Add get_trilio_codename_install_source to attempt to derive the Trilio
version supported by an apt repo.
* Add get_trilio_charm_instance which overrides the default get_charm_instance.
This will pick the correct charm class based on both the Trilio release and
the OpenStack release.
* Add select_trilio_release which overrides the default select_release and
calculates the target OpenStack and Trilio release.
* Add a specialist Trilio metaclass BaseTrilioCharmMeta. This registers
charm classes using their OpenStack release, Trilio release and package
type.
* Move code shared between TrilioVaultCharm & TrilioVaultSubordinateCharm
to TrilioVaultCharmMixin. Add support for Trilio upgrades to
TrilioVaultCharmMixina.
Change-Id: I5a5e5721d9a713b66f8c796896c400481e9733a2
3b72a8ba2f