Sort widgets list based on intent-filter priority.

- Sort based on priority, also group them in PreferenceCategory. So
category is divided by horizontal lines.

- Also removed a bunch of intent-filter for VOICE_LAUNCH. I don't think
we support them any more. If we see bugs, can easily put them back.

Change-Id: I286a6bdf8b3c2eb716a36c6a061fc54a8010d8f6
Fixes: 74806595
Test: manual