Style and code refactor

[bndw]

This pull request includes the following changes:

• Introduction of the Settings component. This component is responsible for all user-controlled settings.
• Rename of the Card component to WifiCard. This component is now a basic WYSIWYG editor.
• All shared state has been lifted up to App.js. Data is sent down into components and actions are raised up. App.js is responsible for managing shared state and composing components.
• Hide password checkbox is no longer ever disabled. It's confusing to a user if the card is WYSIWYG but sometimes they're not able to control certain parts. Now a user can hide the password field, even if it doesn't pass validation -- if there are validation errors they'll get an error message on print with actionable directions.
• A non-breaking copy change to wifi.password.hide, wifi.password.length.5 and wifi.password.length.8 that will need to be ported to all translations

There's still opportunity for more polish and refactoring, but given the [growing] size of this refactor I'd like to land it soon.

Give it a try at: https://dev.wificard.io
I'd appreciate any feedback from the community.

Fixes #111

[olekstomek]

Big refactoring and lots of changes. 👏 I like the WYSIWYG approach.
A good lesson for me about Lifting State Up.
As for me, the changes are good and well-justified. A thumbs up 👍 on my side. 😉