Improve shoppers/people display for Customer tab in profile view

also expose settings for people/clientele handlers

tailbone/templates/customers/configure.mako

@@ -62,6 +62,14 @@
       </b-checkbox>
     </b-field>
 
+    <b-field label="Clientele Handler"
+             message="Leave blank for default handler.">
+      <b-input name="rattail.clientele.handler"
+               v-model="simpleSettings['rattail.clientele.handler']"
+               @input="settingsNeedSaved = true">
+      </b-input>
+    </b-field>
+
   </div>
 
   <h3 class="block is-size-3">POS</h3>