feat, introduce an API Server to run commands through HTTP server

[davidfirst]

To start the server, run bit server, which creates a new express server locally on port 3000.
To run a command on this server, make a POST request to /api/cli/:cmd. Optionally, in the body, add the args and the flags of the command. For example:

http://localhost:3000/api/cli/list

{
    "args": ["teambit.workspace"],
    "options": {
        "ids": true
    }
}

The result is a JSON object with the same output you would get when running the command with --json flag.
If the command doesn't accept json flag, it'll throw a descriptive error about it.

The main goal of this server is to provide a fast way to communicate with bit (e.g. vscode extension makes requests to bit). Because the server is running constantly, there is no bootstrap penalty we have in the CLI. Also, once the components are loaded in-memory, they're accessible immediately at no cost.
It runs a "watcher" in the background to make sure to update/clean the memory cache when needed.