…be updated for CosmosDB accounts

Description

Allow ServerVersion to be updated on CosmosDB accounts. This allows mongo users to update the API version of the mongo account.

Add BackupIntervalInMinutes and BackupRetentionInHours parameters to the New and Update cmdlets of CosmosDB accounts.
(These parameters were part of the following cmdlet review: https://github.com/Azure/azure-powershell-cmdlet-review-pr/issues/701)

Checklist

• I have read the Submitting Changes section of CONTRIBUTING.md
• The title of the PR is clear and informative
• The appropriate ChangeLog.md file(s) has been updated:
  • For any service, the ChangeLog.md file can be found at src/{{SERVICE}}/{{SERVICE}}/ChangeLog.md
  • A snippet outlining the change(s) made in the PR should be written under the ## Upcoming Release header -- no new version header should be added
• The PR does not introduce breaking changes
• If applicable, the changes made in the PR have proper test coverage
• For public API changes to cmdlets:
  • a cmdlet design review was approved for the changes in this repository (Microsoft internal only)
    • {Please put the link here}
  • the markdown help files have been regenerated using the commands listed here