[controller] add rt topic name in store config

[arjun4084346]

Summary, imperative, start upper case, don't end with a period

In future, we want to provide users/admin ability to create a new real time topic, probably with some different configurations, e.g. partition count. This new real time topic would co-exist with the old real time topic, so we want to give a new name to it.
This PR will make all the components check the real time topic's name, if it exists, in Store config. If Store config does not have any name, it would be assumed, that there is no new topic right now and we can use the old methodology "<store_name>_rt" to determine the real time topic name.

Resolves #XXX

How was this PR tested?

added integration tests.

Does this PR introduce any user-facing changes?

• No. You can skip the rest of this section.
• Yes. Make sure to explain your proposed changes and call out the behavior change.