feat: add flag to disable template insights (#20940)

Closes #20399 

To summarize the original commit messages:

- Do not log stats to the database.
- Return errors on the insight endpoints.
- Update the frontend to show those errors.
- Also fixes an issue with getting the user status count via codersdk,
since I added a test to ensure it was not disabled by this flag and it
was sending the wrong payload.

coderd/testdata/insights/user-activity/disabled_week_deployment_wide.json.golden

@@ -0,0 +1,8 @@
+{
+  "report": {
+    "start_time": "2023-08-15T00:00:00Z",
+    "end_time": "2023-08-22T00:00:00Z",
+    "template_ids": [],
+    "users": []
+  }
+}