Prototype launching FED after detecting 5 taps power button

This launches FED, not the panic UI. And it's not launching through
sysui as designed.

It also does not deal with keyguard so screen will flash when tapping 5
times.

Left TODOs in code to fix later.

Test: manual
Bug: 161394591
Change-Id: I9791279a2bc13355a8b79af665ef449cd6040c7b