Support archiving pages

Would you add the option to make a direct saving request to archive.is alias archive.fo ?

If there is already an archive entry for the concerning URL, archive.today show the found entry, and will also ask for a confirmation - like this:

> This page was last archived 99 years ago
> If this snapshot looks obsolete you can again

If the above suggestion is not feasable, maybe the following is:
https://archive.is/?url={?}

Start by reviewing the browser extension's existing archive-provider flow and the archive.is/?url={?} request described in the issue. Determine how a save request and an existing snapshot should be handled, including the confirmation wording, then verify the behavior against archive.is or its archive.fo alias.

Written by the indexing model from the issue text.