Revert "Trebuchet: Use preference provider to lock/unlock homescreen"

This reverts commit 9e3234c57c0ab0a74cdb93972d846d4777258292.
Launcher: Optimize LauncherModel loading + speed tweaks

Credits to aokpx: https://github.com/aokpx/platform_packages_apps_Launcher2/commit/82a7a0b7a7c13cd48ffa2dfe409724a75a03caa1