dev: introduce NullDevConsoleService

In the prod environment there is no instance of DevConsoleService. If
methods are called on the service without a check to see if it exists,
this results in "read on undefined" errors that can only be produced in
a prod environment. This was the cause of the issue caused by the
previous log cleanup PR where it looked like "websockets were broken".
The missing undefined check is fixed by #1734, but the change in this
commit will catch future cases.

Additionally, this change will help with moving away from the dev
console.

src/backend/src/CoreModule.js

@@ -133,7 +133,6 @@ const install = async ({ context, services, app, useapi, modapi }) => {
     const { HTTPThumbnailService } = require('./services/thumbnails/HTTPThumbnailService');
     const { PureJSThumbnailService } = require('./services/thumbnails/PureJSThumbnailService');
     const { NAPIThumbnailService } = require('./services/thumbnails/NAPIThumbnailService');
-    const { DevConsoleService } = require('./services/DevConsoleService');
     const { RateLimitService } = require('./services/sla/RateLimitService');
     const { AuthService } = require('./services/auth/AuthService');
     const { PreAuthService } = require("./services/auth/PreAuthService");
@@ -270,8 +269,12 @@ const install = async ({ context, services, app, useapi, modapi }) => {
     });
     services.registerService('__refresh-assocs', RefreshAssociationsService);
     services.registerService('__prod-debugging', MakeProdDebuggingLessAwfulService);
-    if ( config.env == 'dev' ) {
+    if ( config.env == 'dev' && ! config.no_devconsole ) {
+        const { DevConsoleService } = require('./services/DevConsoleService');
         services.registerService('dev-console', DevConsoleService);
+    } else {
+        const { NullDevConsoleService } = require('./services/NullDevConsoleService');
+        services.registerService('dev-console', NullDevConsoleService);
     }
 
     const { EventService } = require('./services/EventService');

src/backend/src/services/NullDevConsoleService.js

@@ -0,0 +1,29 @@
+const BaseService = require("./BaseService");
+
+/**
+ * When DevConsoleService is not enabled, it is a more robust approach
+ * to replace it with a null implementation rather than not have
+ * 'dev-console' present in the services registry. This is because any
+ * errors caused by accessing methods on 'dev-console' without ensuring
+ * it exists are likely only to be caught in the production environment.
+ */
+class NullDevConsoleService extends BaseService {
+    notice ({ colors, title, lines }) {
+        colors = colors ?? {
+            bg: '46',
+            bginv: '36',
+        };
+
+        console.log(`\x1B[${colors.bginv}m▐\x1B[0m\x1B[${colors.bg}m ${title} \x1B[0m`);
+        for ( const line of lines ) {
+            console.log(`\x1B[${colors.bginv}m▐▌\x1B[0m${line}\x1B[0m`);
+        }
+    }
+    turn_on_the_warning_lights () {}
+    add_widget () {}
+    remove_widget () {}
+}
+
+module.exports = {
+    NullDevConsoleService
+};