Refresh charm to drop release usage in ops-sunbeam.
Drop surplus template fragments.
Refresh unit tests.
Tidy requirements.txt.
Switch to black + other linters.
Tidy docstrings across operator.
Change-Id: Ied1e6a797645f58a84fe4aad20080ba585f54d19
Add project templates and variables to osci.yaml
Add rename script to change built charm name to
charm_build_name defined in osci.yaml
Change-Id: I737badefa19fd8d65def0ab79cadaa63d7d93b5a