fix: ohif-cli cosmetic changes for help description (#2776)

* fix ohif-cli cosmetic changes for help description

* refact code review fix main command name

* fix extension template fix extension-default package version

platform/cli/templates/extension/dependencies.json

@@ -17,7 +17,7 @@
   },
   "peerDependencies": {
     "@ohif/core": "^3.0.0",
-    "@ohif/extension-default": "^1.0.1",
+    "@ohif/extension-default": "^3.0.0",
     "@ohif/extension-cornerstone": "^3.0.0",
     "@ohif/i18n": "^1.0.0",
     "prop-types": "^15.6.2",