Dev: rename 'Score' to 'Kind'

Score is the numeric value of the constraint (or +-INFINITY).
Kind is its kind: Mandatory, Optional, Serialize.

hawk/app/views/orders/_form.html.erb

@@ -9,7 +9,7 @@
       <% end %>
       <div class="form-group" data-help-filter=".row.score" id="order_score_group">
         <label class="col-sm-5 control-label" for="order_score">
-          <%= _("Score") %>
+          <%= _("Kind") %>
         </label>
         <div class="col-sm-7">
           <div class="input-group">