RE action for catching up naming table + typechecking a single file

RE action for catching up naming table + typechecking a single file

Summary:
This diff adds the ability to run hh with the flag --single-remote-execution

Running this will do the following

1) Update both forwards and reverse naming table to catch up with local state. If no saved state exists, it'll download one and bootstrap from that.
2) Typechecks the file you passed in
3) Returns a list of dep edges discovered in JSON format as well as errors discovered in typechecking as basic stdout

The next step is to have a coordinator  that will
1) calculate the fanout
2) acquire a lease if it doesn't yet have one
3) distribute single file actions using hh --single-remote-execution via RE
4) aggregating errors and returning back to user
5) aggregating dep edges and updating dep edges accordingly

In the future we'll likely want to support batch of files. However for the sake of getting a working example, I figured having a single file version is sufficient for now.

Differential Revision: D27555605

fbshipit-source-id: 0d9301b4ede35dbff9be953380b6ec485ef49850