Add orbit icon (#1010)

icons/orbit.json

@@ -0,0 +1,11 @@
+{
+  "$schema": "../icon.schema.json",
+  "tags": [
+    "planet",
+    "space",
+    "physics"
+  ],
+  "categories": [
+    "science"
+  ]
+}

icons/orbit.svg

@@ -0,0 +1,17 @@
+<svg
+  xmlns="http://www.w3.org/2000/svg"
+  width="24"
+  height="24"
+  viewBox="0 0 24 24"
+  fill="none"
+  stroke="currentColor"
+  stroke-width="2"
+  stroke-linecap="round"
+  stroke-linejoin="round"
+>
+  <circle cx="12" cy="12" r="3" />
+  <circle cx="18" cy="6" r="2" />
+  <circle cx="6" cy="18" r="2" />
+  <path d="M18.8,7.8c0.2,0.3,0.4,0.7,0.5,1.1c0.4,1,0.6,2,0.6,3.1s-0.2,2.2-0.6,3.1c-0.4,1-1,1.8-1.7,2.5 s-1.6,1.3-2.5,1.7c-1,0.4-2,0.6-3.1,0.6" />
+  <path d="M5.2,16.2c-0.2-0.3-0.4-0.7-0.5-1.1c-0.4-1-0.6-2-0.6-3.1s0.2-2.2,0.6-3.1c0.4-1,1-1.8,1.7-2.5S7.9,5,8.9,4.6 c1-0.4,2-0.6,3.1-0.6" />
+</svg>