UI: highlight pinned printings in Printing Selector

Fixes #5930.

Signed-off-by: Gauwal <gauwain2611@hotmail.com>

cockatrice/resources/icons/pin.svg

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="utf-8"?>
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100" width="64" height="64">
+  <g transform="matrix(0 1 -1 0 99.465813 0)" opacity="0.7">
+    <path fill="#000000" fill-rule="evenodd" clip-rule="evenodd"
+    stroke="#ffffff"
+          stroke-width="4"
+          stroke-linejoin="round"
+          stroke-linecap="round"
+          d="M65.5 62
+             L78 49
+             C73.5 44.5 69.5 42 63 44
+             L45 31 C47 25 46 22 41.5 18
+             L19 41.5
+             C23 45.5 25 46.5 31 45
+             L44 62.5
+             C42.3 69 45 73.5 49 78
+             L61.5 65.5
+             L84 87
+             L87 87
+             L87.5 86.5
+             L87.5 83.5 Z" />
+  </g>
+</svg>
+