First draft implementation of mocks for dream settings.
Want to merge for the weekly build, so a few things remain, namely:
- flat style for preview/settings buttons + dividers
- animation between dream row expanded/collapsed state
- wire up the help url
- possibly ditch the non-standard style
- add logging
- refresh when packages are installed/uninstalled
Bug:7010260
Change-Id: I96e3ab944170925bd76edf7b8b1127adfffc6262