add Support Panel

Step 1. find panel href={element} in element/root.html

Step 2. find panel element in element/{element}.html
replace the line
`<script src="js/support.js"></script>`
to
`<panel data-path="panels/SupportPanel"></panel>`

Step 3. create new panels/SupportPanel.js and include module/Support

Step 4. create modules/Support.js

Step 5. test with command for integration test
`sudo make test-integration APP=settings2`

or run single test case `./bin/gaia-marionette test_apps/settings2/test/marionette/tests/support_settings_test.js`


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## misc

* replace `Settings.mozSettings` to `navigator.mozSettings`

* file `resources/support.json`, `resources/network.json`, `resources/sensor.json` should be generated dynamically in build script, but it only happens in settings.