15822 state themes nsw

A new NSW theme for aGov, "aGov Waratah".

To test:
- Install aGov as normal, including example content
- Switch to the Waratah theme
- Theme should match, almost exactly, that at: https://redmine.previousnext.com.au/issues/15822

Exceptions:
- Font resize tool is styled differently, as it uses images.

In particular, check that styles.css is enabled by default on install, for that theme. It's set to be on, but sometimes is disabled.