add number_columns option to checklist field

Author: lakuapik

src/resources/views/crud/fields/checklist.blade.php

@@ -31,7 +31,7 @@
 
     <div class="row">
         @foreach ($field['options'] as $key => $option)
-            <div class="col-sm-4">
+            <div class="col-sm-{{ isset($field['number_columns']) ? intval(12/$field['number_columns']) : '4'}}">
                 <div class="checkbox">
                   <label class="font-weight-normal">
                     <input type="checkbox" value="{{ $key }}"> {{ $option }}