Add Wifi Panel

WIFI panel currently only shows the Wifi Slice. It's possible
more slices would be added in the future.

Testing is done here and in CTS.

Test: manual app
Test: robotests
Test: atest SettingsPanelTest
Fixes: 126894142
Change-Id: If691467e7c4bb9edd1b8a1b710c65e93284dc568