feat(@angular/cli): add --defaults option to ng new

Any option with a default value will not be prompted (if a prompt is defined) and the default will be used instead.

Closes angular#12084

Author: clydin

packages/angular/cli/commands/definitions.json

@@ -57,6 +57,11 @@
           "type": "boolean",
           "default": "true",
           "description": "Disables interactive inputs (i.e., prompts)."
+        },
+        "defaults": {
+          "type": "boolean",
+          "default": "false",
+          "description": "Disables interactive inputs (i.e., prompts) for options with a default."
         }
       }
     }

packages/angular/cli/models/schematic-command.ts

@@ -53,6 +53,7 @@ export interface BaseSchematicOptions extends BaseCommandOptions {
   dryRun?: boolean;
   force?: boolean;
   interactive?: boolean;
+  defaults?: boolean;
 }
 
 export interface RunSchematicOptions {
@@ -259,6 +260,11 @@ export abstract class SchematicCommand<
     });
 
     if (options.interactive !== false && process.stdout.isTTY) {
+      if (options.defaults) {
+        (workflow.registry as schema.CoreSchemaRegistry)
+          .addPreTransform(schema.transforms.addUndefinedDefaults);
+      }
+
       workflow.registry.usePromptProvider((definitions: Array<schema.PromptDefinition>) => {
         const questions: inquirer.Questions = definitions.map(definition => {
           const question: inquirer.Question = {