[feat] add reusable tf plan

[AndyBoWu]

Description

Context

We need to use terraform plan and its related commands quite often before officially provision a bunch of cloud resources. This PR is created to group these steps and make them a reusable Github action workflow

Content

This PR adds the following functionalities

1. parse env and aws_region from the given folder path. This means we need to enforce the folder creation and naming convention internally
2. map env to AWS_ACCOUNT_ID which is being used for later iam role defition
3. configure aws credential using OIDC
4. install terraform on the runner to the given terraform_version
5. terraform init
6. terraform validate
7. terraform plan
8. post the output content to the PR when the workflow succeed

Notes

The following inputs are required to invoke this reusable Github action workflow

  workflow_call:
    inputs:
      path:
        type: string
        required: true
        description: 'Path to Terraform configuration'
      role: 
        type: string
        required: true
        description: 'Role to assume in the target AWS account'
      terraform_version:
        type: string
        required: true
        description: 'Terraform version to use'
    secrets:
      AWS_ACCOUNT_DEV_STAGING:
        description: 'AWS account ID for dev or staging environment'
        required: false
      AWS_ACCOUNT_PROD:
        description: 'AWS account ID for production environment'
        required: false