build(aio): change examples to CLI (#19248)

PR Close #19248

aio/tools/examples/shared/boilerplate/cli/src/environments/environment.prod.ts

@@ -0,0 +1,3 @@
+export const environment = {
+  production: true
+};

aio/tools/examples/shared/boilerplate/cli/src/environments/environment.ts

@@ -0,0 +1,8 @@
+// The file contents for the current environment will overwrite these during build.
+// The build system defaults to the dev environment which uses `environment.ts`, but if you do
+// `ng build --env=prod` then `environment.prod.ts` will be used instead.
+// The list of which env maps to which file can be found in `.angular-cli.json`.
+
+export const environment = {
+  production: false
+};