Client Encryption: Adds support to use gateway cache to get client encryption key properties

[aayush3011]

Description

This PR brings in the support to carry out cached reads of client encryption key properties on the gateway cache. The gateway houses a cache for client encryption key properties to reduce throttling on master partitions.

Type of change

[] New feature (non-breaking change which adds functionality)

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[simplynaveen20]

LGTM , apart from some comments