[getting-started] Add an example to create an EC2 instance with user-data script

[tungbq]

Create an ec2/user-data folder under https://github.com/tungbq/aws-lab-with-terraform/tree/main/getting-started.
Then add a terraform code to provision EC2 instance with t2.micro type (we can name it as main.tf)
Adding user data script on boot of EC2 instance, for example we could try to install mysql on the boot.

Reference:

• https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/instance
• https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/instance#user_data