Parent issue: #43110

Similar to #44145 but for Azure cloud provider.

In-tree cloud providers will be disabled by default starting with 1.29 so we want to provide users an option to both:

1. Provision new RKE2 clusters with Azure external (out-of-tree) cloud provider
2. Migrate existing RKE2 clusters that use in-tree Azure cloud provider to external cloud provider.

Supporting this will most likely be down to developing and testing procedure for setting up such external cloud provider but may require code changes (as we needed for the referenced issue for adding AWS cloud provider support).
UI changes may also be needed and it's asked to file rancher/dashboard issue(s) if such changes are determined to be necessary as part of working on this issue.