Add experimental verbose logging flag (#49250)

Only shows fetch request logs by default and allows opting into verbose
request timings via experimental config.

x-ref: [slack
thread](https://vercel.slack.com/archives/C03KAR5DCKC/p1683236293282549)

Author: ijjk

packages/next/src/server/config-schema.ts

@@ -484,6 +484,9 @@ const configSchema = {
             },
           },
         },
+        logging: {
+          type: 'string',
+        },
       },
       type: 'object',
     },

packages/next/src/server/config-shared.ts

@@ -144,6 +144,7 @@ export interface NextJsWebpackConfig {
 }
 
 export interface ExperimentalConfig {
+  logging?: 'verbose'
   appDocumentPreloading?: boolean
   strictNextHead?: boolean
   clientRouterFilter?: boolean

packages/next/src/server/next-server.ts

@@ -1789,7 +1789,7 @@ export default class NextNodeServer extends BaseServer {
               )
             }
             process.stdout.write('\n')
-          } else {
+          } else if (this.nextConfig.experimental.logging === 'verbose') {
             process.stdout.write(
               `- ${chalk.cyan(req.method || 'GET')} ${req.url} ${
                 res.statusCode