[FEATURE] Export as downloadable file, and Drag/drop upload for importing

[mchubby]

Is your feature request related to a problem? Please describe. Export button to generate a timestamped download (blob or data-uri) we can keep instead of copy-pasting, which can be frustrating (click to copy did not live to expectations either). Plus, no need to open an editor, copy paste, save, close.

Import this file using a drag and drop operation based on its naming pattern.

Describe the solution you'd like You can use either a base64 or plaintext data uri, or a Blob if text tends to be large

Describe alternatives you've considered #245 for people willing to log in

Additional context

[EliteMasterEric]

I like this idea. Currently the export button displays the textbox, but it shouldn't be too hard to generate and download a file.

Additionally, I already have drag and drop functionality implemented with the image uploader.