Create default VPC and subnet for 02-overview

[tzujui]

Description

• Create default VPC and subnet using terraform resources
• upgraded aws provider to version 4 to use force_destroy on both resources (see known issues from aws provider below)

Related Issue

Addressed VPCIdNotSpecified error mentioned in #7

How Has This Been Tested?

• Run terraform init and verify that hashicorp/aws v4.x.x is used.
• Run terraform plan and apply.
• Verify that resources are created in AWS console.
• Manually detached and delete default internet gateway and delete subnets. Then, run terraform destroy.
• Verify that resources are destroyed in AWS console. Destroy complete! Resources: 3 destroyed.

Screenshots:

Known issues from terraform-provider-aws

I ran into an issue when destroying the default VPC. The error message is The vpc 'vpc-xxxxxxxxxxxxxx' has dependencies and cannot be deleted. Other resources are implicit created with the aws_deafult_vpc resources so based on AWS's doc, I detached and deleted the default internet gateway and deleted subnet manually in console. Then, run terraform destroy to tear down the default VPC. (I had to run it twice cause the terraform-provider-aws_v4.67.0_x5 plugin crashed due to resource change request being cancelled.) This is the workaround that worked for me.
If you are interested in learning about the root cause, I also found this draft PR and looks like they are working on fixing the default VPC bug caused by IGW. Hope this helps!