Custom namespace names

Currently Keramik chooses the namespace name using the pattern `keramik-{network name}`. We should allow the namespace name to be specified in the network spec.

DOD:

- Its possible to define the namespace name as part of the network spec
- The status reports the name of the namespace
- Tests are updated

Look at the network spec definition to see where namespace naming is currently handled. The operator likely creates namespaces based on a default pattern; modify the spec to accept a custom name field. Update the status reporting to include this namespace name. Check existing tests for namespace creation and update them to cover the new custom name functionality.

Scritto dal modello di indicizzazione a partire dal testo della issue.