Add documentation to cover off backup support with recovery services vaults

[rudolphjacksonm]

Is your feature request related to a problem? Please describe.
Some support for recovery services vaults exists but this is not yet covered in the documentation.

Describe the solution you'd like
Add a page which describes how recovery services vaults are supported and to what degree.

Describe alternatives you've considered
N/A

Additional context
Add any other context or screenshots about the feature request here.