Adding a devcontainer

[koudaiii]

Why

ref https://microsoft.github.io/code-with-engineering-playbook/developer-experience/devcontainers/

I would like to make more people can contribute to Azure Terrafy.

1. When someone develops Azure Terrafy, someone needs to set up a few things ready for the development environment. (e.g. GoLang / Azure CLI / terraform)
2. I want to enable e2e testing by switching to another environment without affecting my existing environment (Azure AD tenant, az config, terraform config, Go version, env, etc.).

I want to use a devcontainer to improve two things. ref https://docs.github.com/en/codespaces/setting-up-your-project-for-codespaces/introduction-to-dev-containers

About dev containers

Development containers, or dev containers, are Docker containers that are specifically configured to provide a full-featured development environment. Whenever you work in a codespace, you are using a dev container on a virtual machine.

What

Set up devcontainer

• Set up Go
• Installing Azure cli
• Installing terraform cli

CONTRIBUTING.md is not in this repository right now, but I would like to describe how to contribute as follows.

How to make the development environment using devcontainer

Using Visual Studio Code with Remote - Containers extension installed, you quickly have your environment set up and ready to go with everything you need to get started.

1. Open this project in VS Code.

2. If Docker isn't already running, make sure it is now.

3. Open the Command Pallet (Command+Shift+P on MacOS or CTRL+Shift+P on Windows). Type Remote-Containers: Open Folder in Container... and hit enter. Or click on the remote container icon in the lower-left corner.

4. VS Code will relaunch and begin building your development container. VS Code will install all the necessary dependencies required for you to begin developing.

5. The container has finished building, open a new terminal in VS Code (Control+Shift+` ) and type:

   vscode ➜ /workspaces/aztfy (koudaiii/devcontainer ✗) $ az version
   {
     "azure-cli": "2.35.0",
     "azure-cli-core": "2.35.0",
     "azure-cli-telemetry": "1.0.6",
     "extensions": {}
   }
   
   vscode ➜ /workspaces/aztfy (koudaiii/devcontainer ✗) $ terraform version
   Terraform v0.15.5
   on linux_amd64
   
   Your version of Terraform is out of date! The latest version
   is 1.1.9. You can update by downloading from https://www.terraform.io/downloads.html
   
   vscode ➜ /workspaces/aztfy (koudaiii/devcontainer ✗) $ az login
   
   ・・・・
   
   vscode ➜ /workspaces/aztfy (koudaiii/devcontainer ✗) $ go build -o bin/aztfy
   vscode ➜ /workspaces/aztfy (koudaiii/devcontainer ✗) $ bin/aztfy <resource group>
   
   ・・・・

6. you can now start developing within the Remote Container environment!

[magodo]

Thanks for this PR!
I have left some additional mostly minor comments that once addressed this should be good to merge 👍

[koudaiii]

@magodo Thank you for your review. I commented and pushed some commits. 😄

[magodo]

LGTM 👍

[koudaiii]

Thank you for your review and your time 😄