CodeGen from PR 19578 in Azure/azure-rest-api-specs

Dev gubalasu frontdoor microsoft.network 2021 06 01 (#19578)

* Adds base for updating Microsoft.Network from version stable/2020-05-01 to version 2021-06-01

* Updates readme

* Updates API version in new specs and examples

* update waf configs and examples from 2020-11-01

* Update api version in new specs and examples

* Migration api update

* Update readme

* Fix readme

* update readme

* Fix readme again

* Fix readme

* Fix readme

* update waf policy provisioning state

Author: SDKAuto