add ability to set date field format

app/javascript/template_builder/builder.vue

@@ -474,6 +474,12 @@ export default {
         field.options = [{ value: '', uuid: v4() }]
       }
 
+      if (type === 'date') {
+        field.preferences = {
+          format: Intl.DateTimeFormat().resolvedOptions().locale.endsWith('-US') ? 'MM/DD/YYYY' : 'DD/MM/YYYY'
+        }
+      }
+
       this.drawField = field
       this.drawOption = null
     },
@@ -650,6 +656,12 @@ export default {
         field.options = [{ value: '', uuid: v4() }]
       }
 
+      if (field.type === 'date') {
+        field.preferences = {
+          format: Intl.DateTimeFormat().resolvedOptions().locale.endsWith('-US') ? 'MM/DD/YYYY' : 'DD/MM/YYYY'
+        }
+      }
+
       const fieldArea = {
         x: (area.x - 6) / area.maskW,
         y: area.y / area.maskH,