build(docs-infra): align code with new CLI v12 apps (#42259)

This commit aligns the angular.io config files more closely to how a
newly generated CLI v12 app would look like. This helps validate the
setup and makes it easier to apply new chages in the future (by
preventing the angular.io layout from deviating too much from the
default new app layout).

PR Close #42259

aio/angular.json

@@ -11,16 +11,19 @@
   "newProjectRoot": "projects",
   "projects": {
     "site": {
-      "root": "",
-      "sourceRoot": "src",
       "projectType": "application",
-      "prefix": "aio",
       "schematics": {
+        "@schematics/angular:application": {
+          "strict": true
+        },
         "@schematics/angular:component": {
           "inlineStyle": true,
           "style": "scss"
         }
       },
+      "root": "",
+      "sourceRoot": "src",
+      "prefix": "aio",
       "architect": {
         "build": {
           "builder": "@angular-devkit/build-angular:browser",
@@ -63,17 +66,19 @@
             ],
             "scripts": [],
             "budgets": [
+              {
+                "type": "initial",
+                "maximumWarning": "850kb",
+                "maximumError": "1mb"
+              },
               {
                 "type": "anyComponentStyle",
-                "maximumWarning": "6kb"
+                "maximumWarning": "2kb",
+                "maximumError": "4kb"
               }
             ]
           },
           "configurations": {
-            "fast": {
-              "buildOptimizer": false,
-              "optimization": false
-            },
             "next": {
               "fileReplacements": [
                 {
@@ -112,18 +117,20 @@
             },
             "ci": {
               "progress": false
+            },
+            "development": {
+              "buildOptimizer": false,
+              "optimization": false,
+              "outputHashing": "none",
+              "vendorChunk": true,
+              "extractLicenses": false
             }
-          }
+          },
+          "defaultConfiguration": "stable"
         },
         "serve": {
           "builder": "@angular-devkit/build-angular:dev-server",
-          "options": {
-            "browserTarget": "site:build"
-          },
           "configurations": {
-            "fast": {
-              "browserTarget": "site:build:fast"
-            },
             "next": {
               "browserTarget": "site:build:next"
             },
@@ -138,8 +145,12 @@
             },
             "ci": {
               "browserTarget": "site:build:ci"
+            },
+            "development": {
+              "browserTarget": "site:build:development"
             }
-          }
+          },
+          "defaultConfiguration": "development"
         },
         "extract-i18n": {
           "builder": "@angular-devkit/build-angular:extract-i18n",