Add instructions for the Python client.

Azure uses the Python client in their Docker image. I've added additional documentation on how to "install" it as well as translations the node.js commands for it.

website/source/docs/builders/azure-setup.html.md

@@ -63,6 +63,14 @@ If you already have node.js installed you can use `npm` to install `azure-cli`:
 $ npm install -g azure-cli --no-progress
 ```
 
+You can also use the Python-based Azure CLI in Docker. It also comes with `jq` pre-installed:
+
+```shell
+$ docker run -it azuresdk/azure-cli-python
+```
+
+As there are differences between the node.js client and the Python client, we've included commands for the Python client underneath each node.js command.
+
 ## Guided Setup
 
 The Packer project includes a [setup script](https://github.com/hashicorp/packer/blob/master/contrib/azure-setup.sh) that can help you setup your account. It uses an interactive bash script to log you into Azure, name your resources, and export your Packer configuration.
@@ -80,6 +88,32 @@ $ azure config mode arm
 $ azure login -u USERNAME
 ```
 
+If you're using the Python client:
+
+```shell
+$ az login
+# To sign in, use a web browser to open the page https://aka.ms/devicelogin and enter the code CODE_PROVIDED to authenticate
+```
+
+Once you've completed logging in, you should get a JSON array like the one below:
+
+```shell
+[
+  {
+    "cloudName": "AzureCloud",
+    "id": "$uuid",
+    "isDefault": false,
+    "name": "Pay-As-You-Go",
+    "state": "Enabled",
+    "tenantId": "$tenant_uuid",
+    "user": {
+      "name": "my_email@anywhere.com",
+      "type": "user"
+    }
+  }
+]
+
+```
 Get your account information
 
 ``` shell
@@ -88,6 +122,11 @@ $ azure account set ACCOUNTNAME
 $ azure account show --json | jq -r ".[] | .id"
 ```
 
+Python:
+```shell
+$ az account set "$(az account list | jq -r '.[].name')"
+```
+
 -> Throughout this document when you see a command pipe to `jq` you may instead omit `--json` and everything after it, but the output will be more verbose. For example you can simply run `azure account list` instead.
 
 This will print out one line that look like this:
@@ -107,6 +146,12 @@ $ azure location list
 $ azure group create -n GROUPNAME -l LOCATION
 ```
 
+Python:
+
+```shell
+$ az group create -n GROUPNAME -l LOCATION
+```
+
 Your storage account (below) will need to use the same `GROUPNAME` and `LOCATION`.
 
 ### Create a Storage Account
@@ -121,9 +166,15 @@ $ azure storage account create \
   --kind storage STORAGENAME
 ```
 
--> `LRS` is meant as a literal "LRS" and not as a variable.
+Python:
 
-Make sure that `GROUPNAME` and `LOCATION` are the same as above.
+```shell
+$ az storage account create -n STORAGENAME -g GROUPNAME -l LOCATION --sku Standard_LRS
+```
+
+-> `LRS` and `Standard_LRS` are meant as literal "LRS" or "Standard_LRS" and not as variables.
+
+Make sure that `GROUPNAME` and `LOCATION` are the same as above. Also, ensure that `GROUPNAME` is less than 24 characters long and contains only lowercase letters and numbers.
 
 ### Create an Application
 
@@ -137,6 +188,12 @@ $ azure ad app create \
   -p PASSWORD
 ```
 
+Python:
+
+```shell
+az ad app create --display-name APPNAME --identifier-uris APPURL --homepage APPURL --password PASSWORD
+```
+
 Password is your `client_secret` and can be anything you like. I recommend using `openssl rand -base64 24`.
 
 ### Create a Service Principal
@@ -153,6 +210,13 @@ $ azure ad app list --json \
 $ azure ad sp create --applicationId APPID
 ```
 
+Python:
+
+```shell
+$ id=$(az ad app list | jq -r '.[] | select(.displayName == "Packer") | .appId')
+$ az ad sp create --appid "$id"
+```
+
 ### Grant Permissions to Your Application
 
 Finally, we will associate the proper permissions with our application's service principal. We're going to assign the `Owner` role to our Packer application and change the scope to manage our whole subscription. (The `Owner` role can be scoped to a specific resource group to further reduce the scope of the account.) This allows Packer to create temporary resource groups for each build.
@@ -164,6 +228,13 @@ $ azure role assignment create \
   -c /subscriptions/SUBSCRIPTIONID
 ```
 
+Python:
+
+```shell
+# NOTE: Trying to assign the role to the service principal by name directly yields a HTTP 400 error. See: https://github.com/Azure/azure-cli/issues/4911
+$ az role assignment create --assignee "$(az ad sp list | jq -r '.[] | select(.displayName == "APPNAME") | .objectId')" --role Owner
+```
+
 There are a lot of pre-defined roles and you can define your own with more granular permissions, though this is out of scope. You can see a list of pre-configured roles via:
 
 ``` shell
@@ -182,6 +253,12 @@ $ azure account show --json \
   | jq ".[] | .id"
 ```
 
+Python:
+
+```shell
+$ az account show | jq -r '.id'
+```
+
 Get `client_id`
 
 ``` shell
@@ -189,6 +266,12 @@ $ azure ad app list --json \
   | jq '.[] | select(.displayName | contains("APPNAME")) | .appId'
 ```
 
+Python
+
+```shell
+$ az ad app list | jq '.[] | select(.displayName | contains("APPNAME")) | .appId'
+```
+
 Get `client_secret`
 
 This cannot be retrieved. If you forgot this, you will have to delete and re-create your service principal and the associated permissions.
@@ -199,14 +282,32 @@ Get `object_id` (OSTYpe=Windows only)
 azure ad sp show -n CLIENT_ID
 ```
 
+Python:
+
+```shell
+$ az ad sp show -n CLIENT_ID
+```
+
 Get `resource_group_name`
 
 ``` shell
 $ azure group list
 ```
 
+Python:
+
+```shell
+$ az group list | jq '.[] | select(.name=="GROUPNAME") | .id'
+```
+
 Get `storage_account`
 
 ``` shell
 $ azure storage account list
 ```
+
+Python:
+
+```shell
+$ az storage account list | jq '.[] | select(.name=="GROUPNAME") | .id'
+```