Implement ProgressStyle indeterminate animation in GM3 style.

Animation per GM3 spec + updated stroke widths for ProgressStyle.

Mostly implemented via an AVD xml (despite its limitations). Registered
an AnimationCallback in NotificationProgressBar.java - this is necessary
to loop the "sequentially" AminatorSet defined in the xml.

Flag: android.app.api_rich_ongoing
Fix: 375239156
Test: Post ProgressStyle indeterminate notifs via test app
Change-Id: I3c02bbe003ca01e75b45cb7b946413d3e6cdc573