Port No-Distribution Screen from Old v2 Branch, Enhance No-Distribution Screen

[dscalzi]

The no-distribution screen should do a version check to see if an update is available. If an update is available, the user should be given an option to update. The update should be performed regardless if the application is closed. This covers the case of a network changing their distribution url and removing the old one after a set period of time.

Related: https://github.com/dscalzi/HeliosLauncher/pull/94 Prerequisite: Auto-updater functionality.