Is your feature request related to a problem? Please describe.
While implementing a fix for another issue, I noticed that database loading appears to always happen on the main thread (e.g. loadEntries() in the EntriesCardAdapter). This is generally a bad practice, and the UI lag may be noticeable on slower devices. I use a Samsung S9 in my everyday usage and haven't noticed it on that device, however I can imagine that on slower/older devices the lag may be more noticeable.

Describe the solution you'd like
Ideally, we could offload database loading and any file parsing onto a background thread. Perhaps we could add a loading progress view (where applicable) while the background work completes.

Additional context
I looked at usages of DatabaseHelper.loadDatabase to find where this was happening, though I believe this may be happening in other places. Adding a quick Application impl for the app with StrictMode thread policy logging enabled can help root out any instances.