[brand] initial - folder src/brand for searxng-wordmark

Folder src/brand is intended to place logo, wordmark and more in.  This commit
moves the origin (source) of searxng-wordmark.svg from the simple theme into
this folder

About the new created src/ folder:

On the long term we can move all the files from static/themes/<name>/src/* into
a src/themes/<name>/* folder.

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

manage

@@ -706,10 +706,9 @@ themes.oscar() {
 }
 
 themes.simple() {
-    local src="searx/static/themes/simple/src"
     local static="searx/static/themes/simple"
     (   set -e
-        convert_if_newer "$src/svg/searxng-wordmark.svg" "$static/img/favicon.png" \
+        convert_if_newer "src/brand/searxng-wordmark.svg" "$static/img/favicon.png" \
                          -transparent white -resize 64x64
         build_msg GRUNT "theme: simple"
         npm --prefix searx/static/themes/simple run build

searx/static/themes/simple/gruntfile.js

@@ -102,7 +102,7 @@ module.exports = function(grunt) {
           svgo: ['--config', 'svg4web.svgo.js']
         },
         files: {
-          '../../../templates/__common__/searxng-wordmark.min.svg': 'src/svg/searxng-wordmark.svg'
+          '../../../templates/__common__/searxng-wordmark.min.svg': '../../../../src/brand/searxng-wordmark.svg'
         }
       }
     },