Support more Azure cloud environments

[AndreasBurger]

How to categorize this issue?

/area usability
/kind enhancement
/platform azure

What would you like to be added:
Currently, the provider-extension is limited in its interaction to the public Azure environment. There are several other Azure environments available globally, most notably Azure Government and Azure China.
Add support to create shoots in these environments.

Why is this needed:
We already have stakeholders that are required to deploy on non-public environments in the near future.