Ring ID memonics

Issue generated from Tuleap's migration script. Originally submitted by: MhhMMM (mhmm)

Add memonics for ring ID to all clients.

Currently the ring ID is accessible only as a 40 char string (random characters).
This is hard to share with a friend in non-digital way. (i.e : Hey, add me on ring ! Sure, what is your ID ? Its ring:xxxxxx.... Ok, I am quite sure I will remember this and add you.. ).

The memonics would map the 40-char ring ID into a few words, for example :
"constant forest adore false green weave stop guy fur freeze giggle clock"
in a similar way as electrum bitcoin wallet exports its seed.
See http://docs.electrum.org/en/latest/faq.html\#what-is-the-seed for details.

This would improve the ease of sharing your ring ID with friends, in any way that does not involve digitally exchanging the 40 char string.