templates: preserve formatting in script output

Use <pre> instead of <samp> to display command output, as <pre>
preserves the new lines and the format of its inner text.

ogcp/templates/actions/script_output.html

@@ -64,7 +64,7 @@
         </div>
         <div id="collapse_{{ loop.index }}" class="collapse" aria-labelledby="heading_{{ loop.index }}">
             <div class="card-body">
-                <p><samp>{{ client['output'] }}</samp></p>
+                <p><pre>{{ client['output'] }}</pre></p>
             </div>
         </div>
     </div>