Streamlining and reliability enhancements

Highlights for this release:

• The role now supports using tags, specifically setup and update-schedule. You don't need to use them, but update-schedule in particular should be useful if you have a slow connection or a slow host and you don't want to wait for all the setup tasks. I recommend running the whole role any time you're using a new version.
• The Chrome PPA no longer breaks when you install Chrome
• Chrome's first-run dialog is now automatically dismissed the first time you run the playbook
• signage-chrome.service uses ExecStartPost now, to avoid piling on a thousand chrome processes because Chrome never fully exits

And more! Check the commit log if you like :)

0.1.0: Functional! Mostly!

This is a working version. It has rough edges, but functions. I want to preserve this moment in time.