[enhancement]: Improve Azure data source with doc/fixes for disk handling

# Enhancement

See discussions in https://github.com/canonical/cloud-init/pull/6243 . Azure data source currently does not handle NVMe but it seems handling NVMe is deprecated. Also[ azure-vm-utils](https://github.com/Azure/azure-vm-utils/blob/main/doc/disk-identification.md) is supposed to now handle all udev rules and atleast there is a plan to migrate udev rules in WALA to that package. cloud-init also has those same rules. Its confusing as hell! We need to remove these udev rules to one place and at least add necessary documentation to that effect. if udev rules are no longer needed or are supported through some other packages, the doc and/or the udev rule file should say so.

This ticket is raised to address all of the above in a way @cjp256 thinks fit.

Start by reviewing the discussion in pull request #6243 and Azure's disk-identification documentation. Then inventory cloud-init's Azure udev rules and related documentation; the work is done when ownership of the rules and NVMe handling is clear and the relevant file or documentation states what is supported.

Written by the indexing model from the issue text.