Quality tab doesn't link to the documentation

[Jorge Castro]

The quality tab shows the X's and checkmarks and the criteria, but we don't tell the user what those criteria means. It should provide a link to: https://juju.ubuntu.com/docs/charm-quality.html

Something like this as an example:

"We rate each charm based on [these criteria](https://juju.ubuntu.com/docs/charm-quality.html) to show you what features this charm provides. Feel free to [https://juju.ubuntu.com/docs/charm-store.html#submitting-a-fix-to-an-existing-charm](contribute to this charm) if it doesn't meet your needs".

The linked doc page ALSO does not explain it to the user, but we're working on fixing that.