CodeGen from PR 14805 in Azure/azure-rest-api-specs

Web ant93.2 2021 01 15 (Azure#14805)

* Adds base for updating Microsoft.Web from version stable/2021-01-01 to version 2021-01-15

* Updates readme

* Updates API version in new specs and examples

* Add Cert and Domain Registration APIs. Fix publishingcredentialpolici… (Azure#14738)

* Add Cert and Domain Registration APIs. Fix publishingcredentialpolicies collection API response. Add networkconfig API verbs for sites and slots

* Fix examples

* Fix issue R4037

* Fix lintDiff issues

* Fix more issues

Co-authored-by: Naveed Aziz <[email protected]>

* Add x-ms-pageable for ListBasicPublishingCredentialsPolicies APIs (Azure#14960)

Co-authored-by: Naveed Aziz <[email protected]>

Author: SDKAuto