Share By Email Extension: Prefill recipient's address

[mjaschen]

It'd be nice to be able to provide an optional default recipient address for the Share By Email extension.

Currently the URLs are formed like this:

mailto:?subject=foobar&body=https://blog.example.org/post-1

With a default recipient address (that has to be entered as option for Share By Email), the URL would look like:

mailto:[email protected]?subject=foobar&body=https://blog.example.org/post-1

[Alkarex]

PR welcome 👍🏻