Remove functionality related to votes demographic info

Since this was giving me too much pain and nobody actually requested
this functionality, I decided to remove it.

config/api.yml

@@ -5,12 +5,6 @@ User:
     debates:    [Debate]
     proposals:  [Proposal]
     comments:   [Comment]
-Voter:
-  fields:
-    gender:     string
-    age_range:  string
-    geozone_id: integer
-    geozone:    Geozone
 Debate:
   fields:
     id:                 integer
@@ -86,4 +80,3 @@ Vote:
     votable_id:       integer
     votable_type:     string
     public_timestamp: string
-    public_voter:     Voter