Switch local store stuff to SQLite use

[vladimiry]

This would enable improved scalability/performance/memory-use, dropping some custom code, etc. The drawback is that some metadata of local store will be open/unencrypted, like for example the number of emails/rows (vs current blob-like store). I'm personally fine with the current implementation, but it doesn't shine brightly for the large local stores (~20k+ emails).

This change would also benefit/unlock the calendar events syncing.

[evilsh3ll]

is there any approssimative ETA for this improvement? thanks🙏

[vladimiry]

No ETA and no guarantee in general that it gets completed. The task is clear, but time-consuming and sort of dull-work one.

I was thinking using Prisma ORM for SQLite wrapping. But my understanding is that programmatically triggered migration and multi-language full-text support is not perfect there yet. Nevertheless, I believe it's good enough for the task.