Update the Dashboard cookbook share content.
Update the Dashboard cookbook share content.

When a user does not own any cookbooks, display the commands for sharing a
cookbooks and add a link to the full docs. This commit removed the info about
the Supermarket Knife plugin since users should be able to just use
regular-ole-knife (ROK) since it follows redirects.

juliandunn/supermarket,nellshamrell/supermarket,juliandunn/supermarket,dpnl87/supermarket,rafaelmagu/supermarket,chef/supermarket,tas50/supermarket,tas50/supermarket,chef/supermarket,robbkidd/supermarket,dpnl87/supermarket,juliandunn/supermarket,nellshamrell/supermarket,jzohrab/supermarket,chef/supermarket,leftathome/supermarket,tas50/supermarket,jzohrab/supermarket,robbkidd/supermarket,chef/supermarket,nellshamrell/supermarket,rafaelmagu/supermarket,tas50/supermarket,juliandunn/supermarket,robbkidd/supermarket,leftathome/supermarket,leftathome/supermarket,jzohrab/supermarket,leftathome/supermarket,rafaelmagu/supermarket,dpnl87/supermarket,robbkidd/supermarket,nellshamrell/supermarket,chef/supermarket,jzohrab/supermarket,dpnl87/supermarket,rafaelmagu/supermarket