Create pod for Compose Notifs

The pod shouldn't depend on SystemUI, so we need to copy over some
utilities like DrawablePainter.

This includes a draft for an initial structure for the library,
including a simple implementation of the standard (null) template.

Note that the Expander implementation is based on the ExpansionControl
implementation from
frameworks/base/packages/SystemUI/compose/features/src/com/android/systemui/notifications/ui/composable/row/NotificationRowPrimitives.kt,
minus the rotation and STL parts for now.

Bug: 431222735
Test: manual in ComposeGallery
Flag: EXEMPT code not in production yet
Change-Id: I04562a33c319a85e78c99bbaa2c3ff1550dd643c