CodeGen from PR 12967 in Azure/azure-rest-api-specs

Request to update Redis Enterprise version stable/2021-03-01 (#12967)

* Adds base for updating Microsoft.Cache from version preview/2020-10-01-preview to version 2021-03-01

* Updates readme

* Updates API version in new specs and examples

* Add support for persistence and fix other typos

* Fix SDK Warning: R2063 OperationIdNounConflictingModelNames

* Fix spellcheck error

* Fix acronym capitalization in descriptions

* Replace local parameters with common-types parameters

* Use naming convention consistent with Azure documentation

* Update word choice, remove deprecated x-ms-code-generation-setting, and fix operationId

* Add x-ms-secret extension and make TLS version a string enum

* Suppress errors about secrets being sent in responses

* Fix operation typo in example