Persistence Storage for Credo-based Mediator

[jeznorth]

Description of feature / user story

As per #2283 the mediator needs to persist messages over restarts so that no information is lost when one or all pods are restarted.

Acceptance Criteria

• One or more messages are sent to the credo mediator
• All the mediator pods are restarted
• A client connects to the newly restarted mediator and is able to fetch all queued messges.

Wireframes or relevant image assets / links

n/a

[jleach]

The current plan is for Timo to refactor the repo layout so that it is in light with the monolithic structure. Then Arial from 2060.io will integrate their work. After this well probably need to update the Helm charts to deploy additional component.s