#257 Missing geometry message red

* changes message colour from blue to red (indicating 'blocking' message)
* only renders message on read_only form e.g. on detail view

templates/map/geom_form.html

@@ -4,9 +4,9 @@
     Encapsules the rendering and initializing of a geometry view component, e.g. used in the detail views.
 {% endcomment %}
 
-{% if geom_form.empty %}
+{% if geom_form.empty and geom_form.read_only %}
     <div class="w-100">
-        <div class="alert alert-info">
+        <div class="alert alert-danger">
             {% fa5_icon 'search-location' %}
             {% trans 'No geometry added, yet.' %}
         </div>