Add Documentation for Track 2 Management SDK (#15096)

* Update docs to reflect Track 2 status

* Update README.md

* Update README.md

* Create previous-versions-quickstart.md

* Update README.md

* Update README.md

* Update README.md

* Update README.md

* Create new-version-quickstart.md

* Update new-version-quickstart.md

* Update README.md

* Update new-version-quickstart.md

* Update new-version-quickstart.md

* Update new-version-quickstart.md

* Update new-version-quickstart.md

* Update new-version-quickstart.md

* add code snipet for resource groups

* update code for vnet

* update

* Update new-version-quickstart.md

* Update new-version-quickstart.md

* Update new-version-quickstart.md

* Update new-version-quickstart.md

* Update new-version-quickstart.md

* Update new-version-quickstart.md

* Update new-version-quickstart.md

* Update new-version-quickstart.md

* Update new-version-quickstart.md

* Update README.md

Co-authored-by: Arcturus <dapzhang@microsoft.com>

* Update documentation/new-version-quickstart.md

Co-authored-by: Arcturus <dapzhang@microsoft.com>

* Update documentation/new-version-quickstart.md

Co-authored-by: Arcturus <dapzhang@microsoft.com>

* Update documentation/new-version-quickstart.md

Co-authored-by: Arcturus <dapzhang@microsoft.com>

* Update README.md

* Update README.md

* Update README.md

* Update documentation/new-version-quickstart.md

Co-authored-by: Arcturus <dapzhang@microsoft.com>

* Update documentation/new-version-quickstart.md

Co-authored-by: Arcturus <dapzhang@microsoft.com>

* Update documentation/new-version-quickstart.md

Co-authored-by: Arcturus <dapzhang@microsoft.com>

* Update documentation/new-version-quickstart.md

Co-authored-by: Arcturus <dapzhang@microsoft.com>

* Update documentation/new-version-quickstart.md

Co-authored-by: Arcturus <dapzhang@microsoft.com>

* Update documentation/new-version-quickstart.md

Co-authored-by: Arcturus <dapzhang@microsoft.com>

* Update documentation/new-version-quickstart.md

Co-authored-by: Arcturus <dapzhang@microsoft.com>

* Update documentation/new-version-quickstart.md

Co-authored-by: Arcturus <dapzhang@microsoft.com>

* Update documentation/new-version-quickstart.md

Co-authored-by: Arcturus <dapzhang@microsoft.com>

* Update new-version-quickstart.md

* Update new-version-quickstart.md

* Update README.md

* Update README.md

* Update new-version-quickstart.md

* Update new-version-quickstart.md

* Update README.md

* Update previous-versions-quickstart.md

* update code snippet

Co-authored-by: ArcturusZhang <dapzhang@microsoft.com>