Expand types of exportable information and formats

[Zweibach]

People have been requesting a lot of features relating to what and how you can export things other than files and tags.

Ability to export more than just files.

• [ ] Keybinds (currently somewhat possible but only one section at a time. A one-file export for all your shortcuts is desired.)
• [ ] Configurations
• [ ] File groups if those gets added

Keybinds and configurations are good for sharing settings between clients. File groups relate to #310.

Ability to export more than just tags with files.

• [x] URLs
• [ ] Dupe information
• [ ] Statistics
• [ ] Ratings
• [x] Notes

There is more to files than just tags. Associated URLs, dupes and alternates, and even statistics to some people, are useful.
Notes will be particularily useful once #259 gets implemented.

More export formats

More export formats than just .txt and the ability to set separation symbol in sidecar .txt files. JSON or XML are the big ones I guess. There should be an equivalent of the Hydrus Tag Archive format for all of the above so you can export information without also having to export the files.

Perhaps even an advanced formatting mode for how you want things exported into files.