Simplify gen_docker_image.sh

[shiranr]

Can the gen_docker_image.sh be simplified by having it as a script in the action:

    CONFIG_PATH="./$USE_CASE_BASE_PATH/experiment.yaml"
    REGISTRY_ENDPOINT="$DOCKER_IMAGE_REGISTRY.azurecr.io"
    FLOW_NAME=$(yq '.flow' "$CONFIG_PATH" |  sed 's/"//g')
    IMAGE_NAME="$REGISTRY_ENDPOINT"/"$USE_CASE_BASE_PATH"/"$FLOW_NAME"_"$DEPLOY_ENVIRONMENT"

    cd docker
    docker compose build --build-arg USE_CASE_BASE_PATH="$USE_CASE_BASE_PATH" --build-arg FLOW_NAME="$FLOW_NAME" promptflow

    docker tag docker-promptflow "$IMAGE_NAME":"$BUILD_ID"
    docker tag docker-promptflow "$IMAGE_NAME":"latest"

    docker push "$IMAGE_NAME":"$BUILD_ID"
    docker push "$IMAGE_NAME":"latest"

[ritesh-modi]

This was because we wanted to generate Docker Image even locally as an optional feature. We can evaluate this issue later if we really need it.