Finer export controls

[aprescott]

I think it would be useful to allow exporting:

• Everything (as now).
• Specific conversations.
• Within specific date ranges.

So for example, if I want to export only a single contact within the last 3 days of conversation, I can set those values in the export screen.

[McLoo]

plus

• the ability to choose a filename (or set the filename from date)
• a "send to" after export option
• (filename chooser for the IMPORT - to be more SMS Backup & Restore compatible)

[chuegel]

First things first. The export/import option is for now broken. See #1186

[aprescott]

@moxie0 seems to have said encrypted backup is broken and apparently due for removal? But either way, plaintext export is still available.

[Awem]

Also nice to have:

• Only export encrypted messages

This way you can avoid including data from imported SMS that is either outdated or includes duplicates (see #780).

[Lyle-Tafoya]

I would also greatly like to be able to export a single conversation. I lost all my conversations by accident and wanted to restore one of them from a backup of the same conversation on my friend's device. I see this issue has been open for about 3 years. Is this something which is planned for the future?

[automated-signal]

GitHub Issue Cleanup:
See #7598 for more information.