nickserv/{info,status}: show entity ID in 'ACC' and 'INFO'

As in issue #253, it would be useful to uniquely identify users across
account renames and such. Privacy issues (/ns info ?<eid>) should not be
a problem, since there already are other ways to chase account renames.
Merge pull request #255 from grawity/entity-id

nickserv/{info,status}: show entity ID in 'ACC' and 'INFO'