Add developer option to launch gesture nav tutorial

This change allows you to start the full, continuous gesture navigation
tutorial by tapping the "Launch Full Gesture Tutorial" option in
launcher developer settings.

Fix: 398018882
Test: Go to developer settings and launch tutorial. It should be
continuous and automatically move on to each gesture.
Flag: EXEMPT bugfix

Change-Id: I5da176e13b4403e1748b9ccba74b24145dafed2c