Updating/work-with this template for GHA and Azd Devcontainer feature.

[zedy-wj]

We are updating this template to support new features in Github Action and Azd Devcontainer.

1. For the Github Action feature: We will remove two lines of code on container image and add GHA code after checkout step in the .github/workflow/azd.yml file. (Shown as below)

2. For the Azd Devcontainer feature: We will add the following code in devcontainer.json file.

"ghcr.io/azure/azure-dev/azd:latest": {}

And remove the relevant code for installing azd in Dockerfile under .devcontainer folder.

RUN curl -fsSL https://aka.ms/install-azd.sh | bash 

@rajeshkamal5050 , @atrakic for notification.