Create cli

[MatthewFlamm]

Create cli to allow for constructing a custom version of this package based on a particular commit ref of a homeassistant/core repo, including the github repo.

This would allow for testing against dev branch if needed.

[MatthewFlamm]

it should be made clear that testing will be more unstable using this method.

[MatthewFlamm]

This approach would have been brittle in the 2021.6.0 cycle as the extraction script needed to be changed. It is only worth it if this is an uncommon occurance.