ACRA is sometimes problematic or annoying. Also, whitelabel versions might
want to disable ACRA. The setting the preference defaultValue is an easy
way to do that.
refs #1483
When debugging issues, tracking the client can be quite useful. This makes
an "Expert" preference that adds the app version and a randomly generated,
stored UUID to the query string each time it downloads an index or an app
package.
This is also useful in whitelabeling, for use cases where there needs to be
some kind of identifier to make it work.
This preference is meant for whitelabel builds that are meant to be
entirely controlled by the server, without user interaction, e.g.
"appliances". Some users have asked for such a thing, so it makes sense to
have it available as an expert preference. In general, we want to ensure
that installs/updates always show a notification so that the user is aware
of what is being installed on their computers. That is the same policy as
other app stores like Google Play, etc.
This removes a layer of redundancy where there were defaults set in the
Preferences class, as well as in preferences.xml. This makes it possible
for whitelabel versions to change the default values of the preferences by
changing it only in preferences.xml.
