Create OAuth Login Flow - Web UI

[spprichard]

Add a login screen, as well as a way to handle the OAuth flow for a first time User. Should allow User to allow our app access to their Meetup data. Similar to the issues in the iOS App, but for the Web UI.

[spprichard]

So this is taking longer then expected, and will probably require 2 separate MR's...I'm 80% done I'd say...will probably want to refactor this code down the road

[spprichard]

So...this work has got me thinking. To consider this work complete, we should probably leave it in a place where a User has logged in, is authenticated, and it left on the "profile" page.

If this is what we want, there will be some more work required to create an authenticated session for the web app, and then we will need to discuss what this looks like in the iOS App.

My goal is to get the Web App / Backend working and creating authenticated sessions by the time the August Meetup rolls around (Aug. 15th). That is also our next milestone so...

I'll keep ya'll posted on the progress!