Docs: delete default VPC and 4 firewalls - created by default on kcc project create - as it will create subnets across all GCP regions prior to na_na1/2 resource restrictions

In the section immediately below
https://github.com/GoogleCloudPlatform/pubsec-declarative-toolkit/blob/main/docs/landing-zone-v2/README.md#option-2---project-in-a-folder

after creating the custom mode VPC

delete the current 4 firewall rules and default VPC

And fix the headers so that the project creation and vpc sections are not directly off the option 2 header - but on its own for option 1 and 2

```
The following
gcloud projects create $PROJECT_ID --set-as-default --folder=$ROOT_FOLDER_ID

will create the default vpc
```