[Feature] introduce key-value separation for big values

### Search before asking

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

### Motivation

If the values is very big, we can separate key and value in the LSM tree，so that we avoid copying the values over and over again during compaction to improve the performance .

refer to https://rocksdb.org/blog/2021/05/26/integrated-blob-db.html

### Solution

_No response_

### Anything else?

_No response_

### Are you willing to submit a PR?

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

The issue names no files, tests, or entry points. Start by locating the LSM-tree implementation, then read the linked RocksDB Integrated Blob DB design to understand the proposed key-value separation; the scope and definition of done still need to be established.

Written by the indexing model from the issue text.