Convert MainPage into a handshake handler

Instead of navigating to / via a browser, we'll be making an AJAX request to /handshake to get all of the information the client needs to connect to another client.
Use /handshake to acquire client information

This means that two clients can connect to one another using only AJAX requests.

Note: `room_key` is currently hardcoded in main.py. There may need to be some kind of lobby to connect clients. We're also doing no room occupancy checks at the moment.
Add more logging to base app to make testing easier.
Add .gitignore
Add client_app.js which is a refactored version of g_screenshare.js.

The new client_app.js file streamlines the client application and makes the
code much easier to follow.
Add client app file
Delete gitignore