Addresses #3104
Added separate answers for the Downloaded vs Play store versions. Also noted that school managed installations would have to be updated by administrators.
Two more questions related to bluetooth on ChromeOS/Android.
They should only be visible if either Chrome or Android is selected, and the `CHROME_APP_RELEASED` feature flag is true.
This keeps the version field empty, as well as the links, until it gets a response from the `version.xml` request. It then displays an error message if there was an error trying to get the version.
Fixes#1351 by including a call to `version.xml` to get the most up-to-date offline build version, defaulting to the current version, `456.0.3`. This also fixes#1352 by switching the route to `/download`, with a redirect from `/scratch2download/`