Summary:
The build process for the server was a simple ts-node that compiled all deps. However, that didn't do any source transformations we need, like replacing `fb-stubs` with `fb` in facebook builds.
This diff works out the dev build process to align more with how other parts of the code base is build, by starting metro to build and bundle the server (only the sources of flipper-server, flipper-server-core and other flipper packages are bundled, node-deps are left as is).
To achieve this, since metro doesn't have support for 'external' packages like any arbitrarily other bundler, we recycle the electronRequire work around that is used in the desktop app as well
Reviewed By: aigoncharov
Differential Revision: D32949677
fbshipit-source-id: 00d326bb17b68aece6fb43af98d0def13b335e74