Create decorator for vault.cache that stores the auth token in a diffrent storage

Problem/Motivation

It may be desirable store key reads in one storage while storing the authentication token in a different storage (read cache in memory and authentication token in APCU) to avoid storage fragmentation or apply different security measures.

Steps to reproduce

N/A

Proposed resolution

Add a decorator for the 'vault.cache' service that will send the authenticaton token (as used by the underlying client) to one cache and all remaining tokens to another.

Remaining tasks

User interface changes

None

API changes

Add new class that will take existing `vault.cache` as an inner service and a second cache for the admin token.

Data model changes

None