In which we restructure the frontend and add some semblance of a README.

This pull request is pretty crucial to the frontend. In here, I've:

* Added a frontend README! Finally. This README includes a great deal of information on the project itself (or, well, the frontend piece of it), the technologies we're using and abusing, how to get started & contribute, the file structure, and other important notes. This can (and will) be improved as we go along, but for now, it's a nice starting point.

* Restructured the frontend. Namely, I've moved all the files we'll need to serve to the frontend (all of our JS, partials, CSS, and vendor files, mainly) to the /static subfolder. This allows us to actually call the files, and use them in the development of the app. Kinda important, natch.

* Removed the outer-level index.html, and integrated our code into the app.html/index.html files in the /templates directory. This may get restructured again at some point, but for now, this is perfectly acceptable. As long as our files get served from somewhere else, we're perfect.

* Accidentally deleted whitespace at the end of the .dev_env file. I'm betting this isn't an issue. But worth noting.

* Gitignored all the .idea files that come with JetBrains products (IntelliJ, PHPStorm [personal fave], WebStorm, etc.). Also, you can see the remnants of where I ignored my .dev_env file temporarily. (Helps keeps committing easy.)

That's about it. Obviously if you have any questions, feel free to ask!

--Maia
I'm not a fan of things like 'Note from X' 'According to Y' and so on in our documentation.  Two main reasons:
* We should be working under the assumption that this codebase will outlive us and we don't want to leave future people scratching their head wonder who Maia is and why they should listen to her.
* We should be shooting for consistency in our codebase.  It shouldn't be 'Walt says this, Maia says that,' it should be 'the codebase says this AND I FOLLOW THE WILL OF THE CODEBASE.'