[dis-psql-operator] Implement db features

### Description

- A DB gets created according to the spec:
```
spec:
  version: 17 # The major version the database server should run
  serverType: dev # How large a server should the database run on. 
  auth:
    adminAppIdentity: my-admin-app-identity 
    userAppIdentity: my-app-identity
```
 

### Additional Information

_No response_