Notification template redesign; part 1.

Known issues:
* Sub-par dyson animation
* Sub-par animation of text in the title
* Notification height limits not yet adjusted
* Decorated custom view height limits not yet updated
* HUNs may need to get their own headerless template
* Messaging style notifications are not yet headerless
* Possible [de]colorization bug for grouped icons
* Some notifications still not always expandable

Bug: 163626038
Test: Manual, visual testing
Change-Id: I9e7e2fd689938a13e042c8f6319bd7d0d2252781