Summary: @public We're moving all the operation from `local-cli` to the `private-cli` and improving the code in the process. On this diff we introduce the `server` command which will be use to start the packager server. On follow up diffs we'll make changes to start using it from `local-cli`.
Reviewed By: @vjeux
Differential Revision: D2531443
fb-gh-sync-id: 5f7f12a250895265d83d1b076f6bbddb5cbdc257