Mutualize backup buckets configuration between clusters

[adejanovski]

k8ssandra-operator doesn’t expose a way of configuring backup buckets which can be reused by different clusters.
Instead, users are forced to repeat connection settings across multiple clusters.
We should instead create a new resource type to materialize reusable Medusa storage settings, which could be referenced in the K8ssandraCluster manifest.

Tasks

Beta Give feedback

1. Create a new MedusaConfiguration API #1157
   0 of 1
   done +1
   
2. Add a field to reference a MedusaConfiguration resource in the K8ssandraCluster API #1158
   3 of 3
   done +1
   
3. Replicate bucket key secrets to namespaces hosting clusters that reference the MedusaConfiguration #1159
   1 of 1
   done +1
   

[rzvoncek]

Subtasks all done, closing the epic.