Consider predictable (generated) names of Backstage runtime objects

[gazarenkov]

For the time we can configure the names of Backstage runtime objects (Deployment, Service, DB related ...)
Which:

• is not necessary b/c we mainly do not care about those names itself, they just have to be unique and preferable somehow associated with root Backstage CR
• may cause consistency problem in case if we update configuration with different name (will probably create another object)
• is not optimal for reconcilation if we do not want to fetch and check default config for created objects as well (can be configurable if we want so)

So the proposal is to make objects' names predictable and (optionally) save the names in the status for better integrity.

NOTES:
- From @rm3l: as commented out in #51 (comment), the Backstage container expects the POSTGRES_HOST env var to be set. Currently, the DB Service has a hardcoded name, but once it has a unique and predictable name, we would need to inject that information into the Backstage container.