Include more DB stats in logs

[Reducing the number of DB queries has made page response times
faster](#2274)

[In Rails 7.2, the default logger started including the number of
database queries in the log](rails/rails#51457).

We already have DB time in the logs. I think it's useful to include the
number of queries as another simple metric.

This is useful for checking performance in local development and I think
probably for production as well. It would enable us to see if the number
of queries is increasing or decreasing over time for specific pages.

Example log entry:

{
  "method": "GET",
  "path": "/forms/1",
  "format": "html",
  "controller": "FormsController",
  "action": "show",
  "status": 200,
  "allocations": 67752,
  "duration": 238.2,
  "view": 23.53,
  "db": 156.87,
  "request_host": "localhost",
  "request_id": "01d5ce3c-7a6c-4d32-9288-cf4350850af3",
  "trace_id": null,
  "form_id": "1",
  "user_ip": null,
  "params": {
    "form_id": "1"
  },
  "queries_count": 26,
  "cached_queries_count": 15
}

Author: thomasiles

app/models/current_logging_attributes.rb

@@ -15,5 +15,7 @@ class CurrentLoggingAttributes < ActiveSupport::CurrentAttributes
             :answer_type,
             :auth0_session_id,
             :validation_errors,
-            :params
+            :params,
+            :queries_count,
+            :cached_queries_count
 end

config/application.rb

@@ -57,7 +57,11 @@ class Application < Rails::Application
     config.lograge.keep_original_rails_log = false
 
     config.lograge.custom_options = lambda do |event|
-      CurrentLoggingAttributes.attributes.merge(exception: event.payload[:exception]).compact
+      CurrentLoggingAttributes.attributes.merge(
+        exception: event.payload[:exception],
+        queries_count: event.payload[:queries_count],
+        cached_queries_count: event.payload[:cached_queries_count],
+      ).compact
     end
 
     # Use custom logger and formatter to log in JSON with request context fields. To use conventional