feat(icons): added graph-hub icon (#4974)

* feat(icons): added split-circles icon

* chore(icons): added cluster tag to `split-circles`

* refactor(icons): renamed `split-circles` to `hub-circles`

* refactor(icons): renamed `hub-circles` to `graph-hub`

* Apply batched suggestions from code review

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

* Fix duplicate 'tags' key in graph-hub.json

Removed duplicate 'tags' key in graph-hub.json.

---------

Co-authored-by: Eric Fennis <eric.fennis@gmail.com>
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

icons/graph-hub.json

@@ -0,0 +1,36 @@
+{
+  "$schema": "../icon.schema.json",
+  "contributors": [
+    "Carlito-la-banane"
+  ],
+  "use-cases": [
+    "Representing a load balancer in cloud infrastructure",
+    "Showing traffic distributed across multiple servers",
+    "Indicating a task split into parallel processes",
+    "Representing a load balancer in cloud service consoles",
+    "Showing incoming traffic distributed across multiple backends",
+    "Indicating a task split into parallel worker threads or processes",
+    "Marking fan-out patterns in system architecture or topology diagrams"
+  ],
+  "tags": [
+    "load balancer",
+    "distribute",
+    "traffic",
+    "network",
+    "nodes",
+    "parallel",
+    "branch",
+    "hierarchy",
+    "routing",
+    "dispatcher",
+    "cluster",
+    "backend",
+    "fan-out",
+    "topology",
+    "orchestration"
+  ],
+  "categories": [
+    "connectivity",
+    "development"
+  ]
+}

icons/graph-hub.svg

@@ -0,0 +1,19 @@
+<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="7" r="4" />
+  <circle cx="4" cy="19" r="2" />
+  <circle cx="12" cy="19" r="2" />
+  <circle cx="20" cy="19" r="2" />
+  <path d="M8 7a4 4 0 0 0-4 4v6" />
+  <path d="M12 11v6" />
+  <path d="M16 7a4 4 0 0 1 4 4v6" />
+</svg>