Caching of external resources

Goal:

To reduce the amount of requests and data required by the TCR Backend, we want to implement a caching solution.

Description:

Our idea is to use HazelCast to provide a distributed cache on the TCR Backend. This will not require any external database and will simplify deployment. It should also work without problems when scaling the TCR Backend to more than one replica.

To enable Hazelcast some kubernetes settings might have to be changed. It will need access to the kubernetes api server, which could be granted via policy.

Acceptance Criteria:

• Caching is implemented in TCR for any outgoing requests. (includes Universal resolver, Trust Lists, VCs, etc.)
• Kubernetes Policy change is requested/done on our deployment clusters if it must be done outside of helm charts. otherwise should be handled in the helm chart issue. If the change must be done outside of helm, It must be documented as part of a installation guide.