CodeGen from PR 15881 in Azure/azure-rest-api-specs

[Hub Generated] Review request for Microsoft.RecoveryServices to add version stable/2021-08-01 (#15881)

* Adds base for updating Microsoft.RecoveryServices from version stable/2021-07-01 to version 2021-08-01

* Updates readme

* Updates API version in new specs and examples

* Fixing readme file

Author: SDKAuto