[simple theme] replace old searx logo by searxng-wordmark.min.svg

Suggested-by: @dalf https://github.com/searxng/searxng/pull/473#issuecomment-962476683
Suggested-by: @MrPaulBlack https://github.com/searxng/searxng/pull/473#issuecomment-962579826
Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

searx/static/themes/simple/src/less/search.less

@@ -18,10 +18,16 @@
 
 #search_logo {
   grid-area: logo;
-}
+  display: flex;
+  align-items: center;
+  justify-content: center;
 
-.search_logo_img {
-  width: 40px;
+  svg {
+    flex: 1;
+    width: 30px;
+    height: 30px;
+    margin: 0.5rem 0 auto 0;
+  }
 }
 
 .search_categories {

searx/templates/simple/search.html

@@ -1,6 +1,7 @@
 <form id="search" method="{{ method or 'POST' }}" action="{{ url_for('search') }}">
   <a id="search_logo" href="{{ url_for('index') }}">
-    <img class="search_logo_img" src="{{ url_for('static', filename='img/favicon.png') }}">
+    <span hidden>SearXNG</span>
+    {% include '__common__/searxng-wordmark.min.svg' without context %}
   </a>
   <div id="search_wrapper">
     <div class="search_box">