Move devices to server folder

Summary:
This is the first of many diffs that extracts the connection, device, client detection out of the flipper core, to create a reusable flipper-server library that can be used in e.g. flipper-dump.

To keep diffs a little smaller, the current connection logic is first moved to the `server/` directory, and decoupled manually from the rest of the core, before moving it over to a separate package.

This first diffs moves the `comms/`, `devices/` and certificate utilities to the `server` directory.

Further untangling will follow in next diffs

Reviewed By: timur-valiev

Differential Revision: D30246551

fbshipit-source-id: c84259bfb1239119b3267a51b015e30c3c080866

desktop/app/src/plugin.tsx

@@ -11,7 +11,7 @@ import {KeyboardActions} from './MenuBar';
 import {Logger} from './fb-interfaces/Logger';
 import Client from './Client';
 import {Component} from 'react';
-import BaseDevice from './devices/BaseDevice';
+import BaseDevice from './server/devices/BaseDevice';
 import {StaticView} from './reducers/connections';
 import {State as ReduxState} from './reducers';
 import {DEFAULT_MAX_QUEUE_SIZE} from './reducers/pluginMessageQueue';