Check for updates using electron-updater, add a Universal 2 build to the releases, and show version information

[paced]

Please explain the problem/why you would want to see a change and any workarounds you might have in place.

It shouldn't be right in-your-face but the app should show the current version and update information on run. We'd need to be less trigger-happy with our release schedule so people won't get annoyed, but this gives people the feeling that this application is maintained and modern.

[paced]

The .blockmap file and electron-builder in general allows automatic updates with deltas. This would be great to implement.

[paced]

As part of this ticket, a Universal 2 option needs to be available. Additionally, the build process for arm64 and i64 is bloody slow. Speeding it up is a secondary concern.

[paced]

I don't know how many subscribers or viewers this Issue has, but this is unlikely to be implemented until after November. Just a heads up. Development will start again in December.