wiki NextGenOnions: add link to contact asn for additions

On wiki:doc/NextGenOnions

[This page will remain read-only for the next few days. Please contact asn for any additions.] But there is no link to send messages. No user page is on Trac as on Wikipedia. Please add asn contact link or edit to say how.

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information