KVS: Ensure tables are cleaned up when files are removed from the KVS

What

Ensure the table containing actions on files is cleaned up after removing a file from the KVS.

Why

This may create a leak that we observed on the DAL node side at a rate of 10MiB/s.

How

We clean-up the file once the remove action is complete.

Manually testing the MR

Check that:

dune exec src/lib_stdlib_unix/test/main.exe -- alcotezt -v

works as expected. Then by removing the last commit, check that the tests now fail.