Exposing custom actions using keyboard shortcut

Keyboard shortcuts:
  ctrl+A => Open all apps
  ctrl+S => shows deep shortcuts
  ctrl+O => shows custom actions popup

This also removes the direct delete/uninstall key shortcuts, making
actidental icon removal less likely

Bug: 24065447
Change-Id: Iae63370c0f33620628567cffd4df024064d4d02e