External HTML crate meta-issue

[Martin1887]

The purpose of this issue is tracking all issues and pull requests proposing features for an external full-featured crate for HTML rendering.

#629 and #631 pull requests propose solving #584 in different manners, and they can inspire an external crate.

#524 asks for opening links in a new tab.

#408 asks for bidirectional text.

#637 asks for lazy loading images.

#802 asks for localized quotes based on language.

Please comment here if a new HTML renderer crate is created, since it could be recommended in docs.

[Martin1887]

#525 implements the opening of links in a new tab.

[notriddle]

#644 proposes a change to the HTML generated by footnotes.

[notriddle]

#806 proposed a change to the HTML generated by task lists.