[Draft] Google drive

[SteveLillis]

@nboughton Here's a first draft. It's built to use Google Drive's AppData feature and attempts to keep the campaigns in sync across devices.

Limitations that I plan to address

• Does not watch files, if a user leaves the browser open on one machine and makes updates on another, they have to refresh the first browser to see those changes
• Does not attempt conflict resolution. If two machines are used to change the same campaign, then there's no merging. One will overwrite the other (whichever one was changed first).
• Needs to be extended to include Assets
• Needs to be extended to show a modal to at least warn when the Google version is ahead of the local version, then can offer to either delete and rewrite the Google or download the Google and overwrite local

I've done my best to follow the patterns I thought I saw in your code. Let me know what you think so far.

[SteveLillis]

@nboughton any thoughts on this so far? Id like your feedback before I spend more time on it in case it goes against any design principles you have with the app