feat: Enable custom support links (#6313)

* backend: support links

* frontend: Support links

* fmt

* test: CODER_SUPPORT_LINKS_0_NAME

* Go tests

* Use UpdateAppearanceConfig

* ui: UpdateAppearanceConfig

* fix: fmt

* Fix: site

* Fix: site tests

* fix: fmt

* fix

* test: check default support links

docs/api/general.md

@@ -879,6 +879,31 @@ curl -X GET http://coder-server:8080/api/v2/config/deployment \
     "usage": "string",
     "value": ["string"]
   },
+  "support": {
+    "links": {
+      "default": [
+        {
+          "icon": "string",
+          "name": "string",
+          "target": "string"
+        }
+      ],
+      "enterprise": true,
+      "flag": "string",
+      "hidden": true,
+      "name": "string",
+      "secret": true,
+      "shorthand": "string",
+      "usage": "string",
+      "value": [
+        {
+          "icon": "string",
+          "name": "string",
+          "target": "string"
+        }
+      ]
+    }
+  },
   "swagger": {
     "enable": {
       "default": true,