[Feature] Introduce BufferWriteManager in rocksdb for controllable memory consume

### Search before asking

- [X] I searched in the [issues](https://github.com/alibaba/fluss/issues) and found nothing similar.

### Motivation

Currently, we will have mutiple rocksdb across tablet servers. And every rocksdbs have their own memeory consumtion. It'll be hard for us to control memory usage in sever level.

### Solution

We can just follow Flink's solution to introduce a buffer writer manger to make all rocksdbs in the server share the buffer writer manger.
See
https://issues.apache.org/jira/browse/FLINK-29928
https://issues.apache.org/jira/browse/FLINK-7289

### Anything else?

_No response_

### Willingness to contribute

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

Start by reviewing how the repository creates and configures its RocksDB instances, then read the linked Flink designs for BufferWriterManager. The work is complete when multiple RocksDB instances on one tablet server share a controllable server-level memory budget, with tests demonstrating the behavior.

Written by the indexing model from the issue text.