[Feature Request] Azure history storage

[elliotpryde]

AWS is the primary cloud provider for a lot of Terraform users, but for many others it's Azure. It would be a lot easier for those people to start using this tool if we were able to use an Azure blob to store history, similar to the Terraform azurerm backend.

If we don't want to set up an AWS account and include more credentials in our CI then the only other option is the local storage option. A local storage backend won't help if you use ephemeral CI agents, or even if you just have more than one and don't want to set up some sort of remote mounted filesystem.

[minamijoyo]

Sounds good. 😄 The history storage interface is designed to be easily extensible if you are familiar with cloud provider APIs. For example, the S3Storage implementation is as follows:
https://github.com/minamijoyo/tfmigrate/blob/v0.2.3/history/storage_s3.go

I would be happy to review it if anyone implements it.