CodeGen from PR 23532 in Azure/azure-rest-api-specs

[Hub Generated] Review request for Microsoft.DocumentDB to add version stable/2023-04-15 (#23532)

* Adds base for updating Microsoft.DocumentDB from version stable/2023-03-15 to version 2023-04-15

* Updates readme

* Updates API version in new specs and examples

* add continuoustier and oldestrestorabletimestamp

* add instantScaleUpValue and softMaxQuota response header to throughput GET calls

* Added SecuredByPerimeter enum value

* update name of ThroughputSettingsResource

* fix header names

* fix header types

* prettier

* fix one typo

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Co-authored-by: Liana Najaroen <lnajaroen@microsoft.com>
Co-authored-by: Praful Johari <pjohari@microsoft.com>