upgrades: Move FreedomBox version information to this app

As noted in #1332 (closed), #1375 (closed) and #1377 (closed), it is best to show the version of FreedomBox package in software updates module. When showing the information in upgrades module, consider showing the icons shown in #1375 (closed) for the two states (up-to-date and outdated).

Further, I would suggest retaining the information in about page for people how expect it to be in about page (many interfaces like Android, Firefox, etc.). I this case, link "new version" text to software updates module.