[simple] ImageLayout.watch: `img_load_error.svg` if img load fails

Show default image `img/img_load_error.svg` when image can't be loaded.

----
Some words about class ImageLayout:

The https://github.com/searxng/searxng/blob/master/searx/static/themes/simple/js/searxng.js is build by a grunt task ..

https://github.com/searxng/searxng/blob/d0e21a01b4e14df905f25445a3f6bcbec481671c/searx/static/themes/simple/gruntfile.js#L91-L93

The `/__common__/js/*.js` concats also https://github.com/searxng/searxng/blob/master/searx/static/themes/__common__/js/image_layout.js where a modified copy of the of the "Google-image-layout" (`ImageLayout`) is implemented [1][2][3].

[1] https://ptgamr.github.io/2014-09-12-google-image-layout/
[2] https://ptgamr.github.io/google-image-layout/src/google-image-layout.js
[3] https://github.com/ptgamr/google-image-layout/tree/master
----

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

1 files changed, 71 insertions, 0 deletions

diff --git a/src/brand/img_load_error.svg b/src/brand/img_load_error.svg
new file mode 100644
index 000000000..4bd867c5c
--- /dev/null
+++ b/src/brand/img_load_error.svg
@@ -0,0 +1,71 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<svg
+   xmlns:dc="http://purl.org/dc/elements/1.1/"
+   xmlns:cc="http://creativecommons.org/ns#"
+   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+   xmlns:svg="http://www.w3.org/2000/svg"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
+   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
+   id="svg8"
+   version="1.1"
+   viewBox="0 0 92 92"
+   height="92mm"
+   width="92mm"
+   sodipodi:docname="img_load_error.svg"
+   inkscape:version="0.92.5 (2060ec1f9f, 2020-04-08)">
+  <sodipodi:namedview
+     pagecolor="#ffffff"
+     bordercolor="#666666"
+     borderopacity="1"
+     objecttolerance="10"
+     gridtolerance="10"
+     guidetolerance="10"
+     inkscape:pageopacity="0"
+     inkscape:pageshadow="2"
+     inkscape:window-width="3840"
+     inkscape:window-height="1536"
+     id="namedview10"
+     showgrid="false"
+     inkscape:zoom="2.2374547"
+     inkscape:cx="-12.067286"
+     inkscape:cy="218.38203"
+     inkscape:window-x="0"
+     inkscape:window-y="27"
+     inkscape:window-maximized="1"
+     inkscape:current-layer="svg8" />
+  <defs
+     id="defs2" />
+  <metadata
+     id="metadata5">
+    <rdf:RDF>
+      <cc:Work
+         rdf:about="">
+        <dc:format>image/svg+xml</dc:format>
+        <dc:type
+           rdf:resource="http://purl.org/dc/dcmitype/StillImage" />
+        <dc:title />
+      </cc:Work>
+    </rdf:RDF>
+  </metadata>
+  <path
+     d="M 39.581382,41.421315 H 30.62689 v -1.21543 q 0,-2.033984 0.818554,-3.59668 0.818555,-1.5875 3.447852,-4.018359 l 1.5875,-1.438672 q 1.413867,-1.289844 2.058789,-2.43086 0.669727,-1.141015 0.669727,-2.282031 0,-1.736328 -1.190625,-2.703711 -1.190625,-0.992188 -3.323828,-0.992188 -2.00918,0 -4.340821,0.84336 -2.331641,0.818554 -4.861719,2.455664 v -7.788673 q 3.001367,-1.041796 5.481836,-1.53789 2.480469,-0.496094 4.787305,-0.496094 6.052344,0 9.227344,2.480469 3.175001,2.455664 3.175001,7.19336 0,2.430859 -0.967383,4.365625 -0.967383,1.909961 -3.299024,4.117578 l -1.5875,1.413868 q -1.686719,1.53789 -2.207617,2.480469 -0.520899,0.917773 -0.520899,2.033984 z m -8.954492,3.671094 h 8.954492 v 8.830469 H 30.62689 Z"
+     style="font-style:normal;font-variant:normal;font-weight:bold;font-stretch:normal;font-size:50.80000305px;line-height:1;font-family:'DejaVu Sans';-inkscape-font-specification:'DejaVu Sans Bold';display:inline;fill:#db3434;fill-opacity:1;stroke-width:0.26458335"
+     id="path827"
+     inkscape:connector-curvature="0" />
+  <circle
+     style="fill:none;fill-opacity:1;stroke:#db3434;stroke-width:10;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1"
+     id="path834"
+     cx="35"
+     cy="36.486031"
+     r="30" />
+  <rect
+     style="opacity:1;fill:#db3434;fill-opacity:1;stroke:none;stroke-width:8;stroke-miterlimit:4;stroke-dasharray:none;stroke-opacity:1"
+     id="rect912"
+     width="18.846331"
+     height="39.963303"
+     x="-12.021294"
+     y="80.490318"
+     ry="1.8669105e-13"
+     transform="rotate(-46.234709)" />
+</svg>