Support setting Azure disk SKUs in machines

[embik]

Description of the feature you would like to add / User story

As a cluster administrator I would like to chose the SKU/type of disks in Azure nodes in order to run nodes with an optimised disk type

Solution details

• machine-controller added support for Azure disk SKUs in https://github.com/kubermatic/machine-controller/commit/1c8c76dfc2150b11e60ba82d69cd2de8ec9ecd33. This needs to be exposed to KKP users via API and/or UI.
• The Kubermatic API needs an API to query for available disk SKUs for a chosen VM SKU.

Alternative approaches

Use cases

The disk SKUs are chosen by Azure automatically based on the VM SKU. Users want to be able to chose a different disk type than what Azure selects, because there is significant cost saving or performance optimisation (via better disk IOPS) possible with the right disk types.

Additional information