Add support for cloud storage

[synox]

To sync multiple browsers, also between firefox and chrome.

Open questions:

• Which storage provider? It has to be simple, ideally no server needed.
• Which authentication? I prefer none, maybe just use an shared url.

[Wyrrrd]

Maybe have a look at the storage area storage.sync, using Chrome's native browser sync feature for simplicity.

The quota is pretty small though...

[synox]

Possible cloud / sheet providers, that the user can control themselves:

• https://www.zoho.com/sheet/developers.html and https://www.zoho.com/sheet/help/api/v2/ (free)
• https://supabase.com (500MB database)
• https://deno.com/deploy/pricing (1 GB)

[synox]

Or maybe sync with a local file that can then be synced with dropbox or gdrive.

[synox]

more options:

• https://www.npoint.io (Editing data over the API via POST requests is in private beta.)
• https://jsonbin.io (free: Upto 100kb, not enough)
• https://jsonbin.org/ (1 MB limit, https://github.com/remy/jsonbin/issues/48)
• https://jsonsilo.com/ (5 MB)
• https://getpantry.cloud/ (deleted after 30 days)

[ariaieboy]

Or maybe sync with a local file that can then be synced with dropbox or gdrive.

To start this option is very good we can sync the file using any cloud storage that we want.