[FEATURE] Incremental Exports

[KnugiHK]

Is your feature request related to a problem? Please describe.
The current implementation only allows the entire database to be exported with each attempt, making incremental exports impossible.

Describe the solution you'd like
Implement a checkpoint file that tracks which message and the previous page number for each chat, allowing future exports to continue from where the last one left off.

Additional context

Discussed in #92

^{Originally posted by msloco March 27, 2024}
Another story is the database and its "export" to behave incrementally. Has anyone managed to do so ? or is it possible to run the exporter on two separate .db but pointing for the output to the same directory with some paging strategy so to make the following exports not to overwrite the previous ones ?

[connect-mahdi]

It might be a great feature ! Maybe similar projects have implemented it (Signal export or Telegram export projects ?)

[KnugiHK]

It might be a great feature ! Maybe similar projects have implemented it (Signal export or Telegram export projects ?)

I'm not aware of any other projects that have implemented it. If you come across one, please share!