Is stream column family useful to be a seperate cf instead of merging into subkey cf?

### Search before asking

- [X] I had searched in the [issues](https://github.com/apache/kvrocks/issues) and found no similar issues.

### Motivation

As title, should we merge it to subkey cf while keeping compatible to old versions?

### Solution

- check the current cfs using `ListColumnFamilies()` before opening db:
- if it's a new database or no stream cf:
- don't create stream cf, use default as stream cf
- if there's stream cf:
- keep to use stream cf for compatibility

### Are you willing to submit a PR?

- [ ] I'm willing to submit a PR!

Start by tracing database column-family initialization and the existing ListColumnFamilies() compatibility check. Verify behavior for new databases without a stream column family and existing databases with one; done means the chosen column family works in both cases without breaking compatibility with older versions.

Written by the indexing model from the issue text.