Add optional user side logging for anomaly debugging help

[MrCsabaToth]

There's a https://pub.dev/packages/logging package. The feature and level could be turned on by the user. Then it'd log entries to the database. The user could download a digest of that log (text file) and email it to me. For safety the logging would rotate in case the user forgets to turn it off. Mostly exceptions would be logged.

[MrCsabaToth]

We'll use https://pub.dev/packages/flutter_logs because that's not revolving around pretty colorful printing, but rather multi-day logs, segmentation, out-of-the box log export (in zip file) and log clearing. Although Android + iOS only (no web or desktop) but this will serve us way better.

[MrCsabaToth]

Ref umair13adil/flutter_logs#30 and umair13adil/flutter_logs#29