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: I75df01d000d74878e7313fa556b16eef2ca4c9ff
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: I746b8a5964bd5f8ab43616b1820981567729278c