support custom icons

sample/icons/cmp.svg

@@ -0,0 +1,6 @@
+<svg stroke="currentColor" fill="currentColor" stroke-width="0" viewBox="0 0 24 24" height="200px" width="200px"
+    xmlns="http://www.w3.org/2000/svg">
+    <path
+        d="M6.01 2c-1.93 0-3.5 1.57-3.5 3.5 0 1.58 1.06 2.903 2.5 3.337v7.16c-.001.179.027 1.781 1.174 2.931C6.892 19.64 7.84 20 9 20v2l4-3-4-3v2c-1.823 0-1.984-1.534-1.99-2V8.837c1.44-.434 2.5-1.757 2.5-3.337 0-1.93-1.571-3.5-3.5-3.5zm0 5c-.827 0-1.5-.673-1.5-1.5S5.183 4 6.01 4s1.5.673 1.5 1.5S6.837 7 6.01 7zm13 8.163V7.997C19.005 6.391 17.933 4 15 4V2l-4 3 4 3V6c1.829 0 2.001 1.539 2.01 2v7.163c-1.44.434-2.5 1.757-2.5 3.337 0 1.93 1.57 3.5 3.5 3.5s3.5-1.57 3.5-3.5c0-1.58-1.06-2.903-2.5-3.337zm-1 4.837c-.827 0-1.5-.673-1.5-1.5s.673-1.5 1.5-1.5 1.5.673 1.5 1.5-.673 1.5-1.5 1.5z">
+    </path>
+</svg>

sample/node-config.b3-setting

@@ -22,6 +22,7 @@
   {
     "name": "Cmp",
     "type": "Condition",
+    "icon": "icons/cmp.svg",
     "doc": "+ 若值为空，返回失败\n+ 非整数类型可能会报错\n",
     "input": [
       "值(int)"