CodeGen from PR 15496 in Azure/azure-rest-api-specs

[DO NOT MERGE]Dev resourcemover microsoft.migrate 2021 08 01 (#15496)

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

* Updates readme

* Updates API version in new specs and examples

* Added systemData property in Move Collection & Move Resource object

* Update resourcemovercollection.json

Added Tags and User-Managed Identities Properties

* Update resourcemovercollection.json

Made changes for removing tags property for document resources and resource group.

* Removed additional empty line

* Swagger PrettierCheck

* Updating examples for 2021-08-01 version.

* CI Fix

Co-authored-by: Anany Shah <anashah@microsoft.com>
Co-authored-by: yashjain4 <87814230+yashjain4@users.noreply.github.com>

Author: 3 people