improve PPI filter layout for compounds list.

Former-commit-id: a5d14f91100455e8b2be3c42600f9c1dac44ec3f

ippisite/ippidb/templates/compound_list.html

@@ -10,16 +10,17 @@
 <div class="row flex-xl-nowrap">
   <div class="col-12 col-md-3 col-xl-2 bd-sidebar">
 <form>
-  <div class="form-group row">
-    <div class="form-check">
+  <fieldset class="form-group row border border-info">
+    <div class="bg-info col-12"><legend>PPI</legend></div>
     {% for ppi in ppis|slice:":5"  %}
+    <div class="form-check col-12">
       <label class="form-check-label">
+        <input class="form-check-input text-right" type="checkbox" value="{{ ppi.id }}" onchange="this.form.submit()" name="ppi" style="width: auto; margin-right: inherit!;">
         {{ ppi.name }}
-        <input class="form-check-input" type="checkbox" value="{{ ppi.id }}" onchange="this.form.submit()" name="ppi">
       </label>
-    {% endfor %}
     </div>
-  </div>
+    {% endfor %}
+  </fieldset>
 </form>
 </div>
 <main class="col-12 col-md-9 col-xl-10 py-md-3 pl-md-5 bd-content" role="main">