[native] Implement filesystem media cache

Summary:
This diff implements native methods to manage media cache stored in filesystem: the tmp_dir/media-cache directory.

Depends on D7251

Test Plan: Tested together with parent diff - saved some files to cache and then retrieved it. It is possible to print the cache path and open it with Finder to inspect what files are inside.

Reviewers: atul, marcin, kamil, ashoat

Reviewed By: ashoat

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D7252