Fix version check

[bemusementpark]

0. Schedule the fetch 4 hours after last check if it was within 4 hours, instead of just 4 hours from now.

1. Renamed versionUtil to VersionDataFetcher

• It has state, so it's not a Util
• It fetches VersionData

2. Fixed an issue where we would never start checking after creating or loading an account (until we background and foreground the app again, at least)

3. Fixed the timing issue where if we checked 1 second before the last check had expired, we would wait another 4 hours, meaning we would call up to 8 hours since the last call.

4. Removed job?.cancel() as the Job was not cancellable, so achieved nothing, but looked like it was doing something, which was potentially misleading.

5. call stopTimedVersionCheck() at the start of startTimedVersionCheck() to prevent any duplicates being posted.

6. Utilise delayTimeMillis < 0 { post immediately } in Handler.postDelayed for simplified code.

• We no longer need to check at the start of fetchVersionData as it's always scheduled at the correct time.
• We no longer need to fetch and schedule, as we schedule to now if appropriate.

7. @Inject it.