Implement LocalColorExtractor using colorkt-based theme engine

This adds an implementation of the LocalColorExtractor interface,
including:
  - Local color extraction using WallpaperManager
  - Theme generation using our colorkt-based dynamic theme engine
  - Resource overlay generation
  - View bounds calculation
    This code comes from AOSP commit 88b7f6a0d ("Move color extraction
    utils to extractor class so each instance can have its own set of
    temp variables.") where it was removed. It appears to be virtually
    identical to the Pixel implementation of LocalColorExtractor as of
    SPB5.210812.002.

These features are necessary for local widget colors, as well as local
colors for popup menu items.

Requires overlay commit to specify the ThemedLocalColorExtractor class name.

Demo screenshots: https://twitter.com/kdrag0n/status/1445961943856992258

Change-Id: I70b4987417531a6ef431e7574db17fea7844f024
2 files changed