Add a Python Azure Webserver example

[swgillespie]

Adds an example using Python to deploy a web server on Azure.

Currently does not work and can't be merged, for two reasons:

1. The most recently released version of pulumi doesn't have a fix for Resource IDs are always the empty string during previews pulumi#2450, this can be worked around with pip install --pre pulumi
2. Python values coming from the engine are always strings pulumi#2459 means that the trick of using a data source to retrieve a virtual machine's IP does not work

[swgillespie]

Update on this PR:

It's still not working, there's still some sort of type confusion happening:

    error: Program failed with an unhandled exception:
    error: Traceback (most recent call last):
      File "/usr/local/pulumi/bin/pulumi-language-python-exec", line 85, in <module>
        loop.run_until_complete(coro)
      File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/asyncio/base_events.py", line 467, in run_until_complete
        return future.result()
      File "/Users/swgillespie/go/src/github.com/pulumi/examples/azure-py-webserver/venv/lib/python3.6/site-packages/pulumi/runtime/stack.py", line 38, in run_in_stack
        await RPC_MANAGER.unhandled_exeception()
      File "/Users/swgillespie/go/src/github.com/pulumi/examples/azure-py-webserver/venv/lib/python3.6/site-packages/pulumi/runtime/rpc_manager.py", line 68, in rpc_wrapper
        result = await rpc_function(*args, **kwargs)
      File "/Users/swgillespie/go/src/github.com/pulumi/examples/azure-py-webserver/venv/lib/python3.6/site-packages/pulumi/runtime/resource.py", line 226, in do_register_resource_outputs
        serialized_props = await rpc.serialize_properties(outputs, {})
      File "/Users/swgillespie/go/src/github.com/pulumi/examples/azure-py-webserver/venv/lib/python3.6/site-packages/pulumi/runtime/rpc.py", line 57, in serialize_properties
        result = await serialize_property(v, deps, input_transformer)
      File "/Users/swgillespie/go/src/github.com/pulumi/examples/azure-py-webserver/venv/lib/python3.6/site-packages/pulumi/runtime/rpc.py", line 145, in serialize_property
        value = await serialize_property(value.future(), deps, input_transformer)
      File "/Users/swgillespie/go/src/github.com/pulumi/examples/azure-py-webserver/venv/lib/python3.6/site-packages/pulumi/runtime/rpc.py", line 135, in serialize_property
        future_return = await asyncio.ensure_future(value)
      File "/Users/swgillespie/go/src/github.com/pulumi/examples/azure-py-webserver/venv/lib/python3.6/site-packages/pulumi/output.py", line 141, in run
        return await cast(Awaitable[U], transformed)
      File "./__main__.py", line 73, in get_public_ip
        ip_result = await network.get_public_ip(name=public_ip_name, resource_group_name=resource_group_name)
      File "/Users/swgillespie/go/src/github.com/pulumi/examples/azure-py-webserver/venv/lib/python3.6/site-packages/pulumi_azure/network/get_public_ip.py", line 100, in get_public_ip
        id=__ret__.get('id'))
      File "/Users/swgillespie/go/src/github.com/pulumi/examples/azure-py-webserver/venv/lib/python3.6/site-packages/pulumi_azure/network/get_public_ip.py", line 34, in __init__
        raise TypeError('Expected argument idle_timeout_in_minutes to be a int')
    TypeError: Expected argument idle_timeout_in_minutes to be a int

Clearly something is coming back to Python as a string when it should have been an int.

[swgillespie]

ping - this is now working and ready to review.

[lukehoban]

If possible - could we add test coverage as well so that we run this for regression prevention nightly?

[swgillespie]

The test failure is unrelated, the new test passes.

[swgillespie]

#260