Upload Nifi flow templates via REST API after Terraform deployment

[paullatzelsperger]

After everything is deployed to Azure, we need to deploy the default TwoClouds.xml flow template and start the root process group. A provider for Terraform can be found here.

Currently the main problem is how to authenticate against Nifi with OpenID - that requires user interaction.

We probably need input from MSFT`s experts on Nifi on how to best authenticate a machine client to Nifi.

Note: since we're invoking terraform from a command line where we need to be logged in to az cli, we might be able to salvage those credentials?