Toggle to switch recent panels styles (1/2)
- Allows us to switch between Stock or Slim recent panles;
- Made TRDS work in theme changes;
- Some minor codes improvments;

This was based on: https://github.com/AOSB/android_frameworks_base/commit/dbb5540884826786bfec9f7ea42a515a09c4094e
Thanks @codex-corp

Change-Id: Ie4c7497de93f1cbdec077657c21bed3766043187