Clean provider, always unshallow git repository and add new deploy method by archive

[Soulou]

For the scalingo provider:

• Remove flag --branch unused and unusable by users
• Add flag --deploy-method allowing the ability to deploy through git or archive quite similar to provider heroku:api vs heroku:git but gathered together.
• With git method, always unshallow git repository to allow git push without any warning/error

[Soulou]

ping @native-api? Are you the right person for dealing with the update of providers?

[native-api]

I'm not.