Traceur: Increase minSdk, remove QuickSettings code for old versions.

Traceur isn't going to be used on pre-N devices at this point. This
change removes the version compatibility code for Quick Settings support
and increases the minSdk to 23 (M).

Bug: 71862209
Test: Tested Traceur functionality through the app and using the QS
setting on a tip of tree Android build.
Change-Id: I5f5e91d34dfd07f6a3a9cf700ebee51f25ada492
6 files changed
tree: feb42178a541b0cad0ce70afb10aa1eb96d34727
  1. res/
  2. src/
  3. Android.mk
  4. AndroidManifest.xml