Rename project and docs to better explain what Wendy does

[levibostian]

I have always called it a background queue. Because it's a queue that runs in the background. But, through conversations with devs, this pitch is not working. People do not understand what Wendy is from this pitch.

Tasks

• Improve the copy in our docs that explain what wendy does. It's a syncing tool.
• Possibly rename project to something that uses sync in the name.

Goal

• Someone who has never heard of Wendy can understand it's value in 5 seconds. 1 sentence.