Support for shared content URI's for automatic backups

[jasger9000]

Checklist

• I made sure that there are no existing issues - open or closed - to which I could contribute my information.
• I made sure that there are no existing discussions - open or closed - to which I could contribute my information.
• I have read the FAQs inside the app (Menu -> About -> FAQs), in the README and my problem isn't listed.
• I have taken the time to fill in all the required details. I understand that the bug report may get dismissed otherwise.
• This issue contains only one feature request.
• I optionally donated to support the Fossify mission.

Which apps should have this feature?

Calendar, Notes

Feature description

When enabling the automatic backup function, it is only possible to back up files to a directory inside the Internal filesystem. It would however be great to be able to specify a shared URI to another storage location provided by a different application. For example, the app CIFS Document provider provides a storage URI (smb://<share_name>) and a shared URI (content://<appid>/tree/<share_id>) to a remote SMB network share. If you were able to provide the shared URI to the backup function, you then would be able to back up your files to other storage systems, not just your device's one.

Why do you want this feature?

I like to back up my files, not on the device on which the original copy is stored anyway, since if I were to lose my phone that wouldn't really be useful in any capacity. So if I wanted to back up anything, I would either need to enable the automatic backups for an internal folder and then manually copy those over to my network share, or remember to hit the export button myself every few days or so. Either one of those is not ideal and also prone to just forgetting it, and therefore not a good solution.

Additional information

The default android file picker that's used if you manually export notes supports remote locations (like Google Drive or CIFS), however I don't know the implementation details for that feature, and my guess is that it just returns a file descriptor. But if not, it may be possible to use it to pick a remote location, instead of the current system, so the user wouldn't need to know the shared URI to that location.