Allow scaling of RLSs

[stefanbethke]

Is your feature request related to a problem? Please describe.

At the moment, the Operator can create a setup with zero, one, or more RLS, and configure the number of CAEs to be run, see #10.

In situations where demand changes significantly, it would be beneficial to be able to scale the number of RLSs available. CoreMedia recommends to have no more than 8 CAEs per RLS.

Since the RLS are stateful, the operator would need the capability to create a new database schema and populate it from an existing RLS schema. This likely requires very specific code to work with the k8s cluster and the database service.

Describe the solution you'd like
By modifying the number of RLS in the custom resource, the Operator automatically creates additional RLS schemata, populates them from either an existing RLS or the MLS, and brings up the new RLS.

Describe alternatives you've considered
Currently, the only way to do this for a running install is to manually create the necessary database schemata and populate them, before increasing the number of RLS.