Summary:
Add compaction API for secondary instance, which compact the files to a secondary DB path without installing to the LSM tree.
The API will be used to remote compaction.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8171

Test Plan: `make check`

Reviewed By: ajkr

Differential Revision: D27694545

Pulled By: jay-zhuang

fbshipit-source-id: 8ff3ec1bffdb2e1becee994918850c8902caf731