Feature root_volume_size on azure-chroot

_This issue was originally opened by @reginaldomoura as hashicorp/packer#10123. It was migrated here as a result of the [Packer plugin split](https://github.com/hashicorp/packer/issues/8610#issuecomment-770034737). The original body of the issue is below._

Hello Everyone,

We have a project running on Azure Cloud and one of the applications used by our team is Packer, but from know we decided to improve the time consume inside of our pipeline, an good aprouch is use azure-chroot.

So now we have an issue and may this is solved before, on aws-chroot we use root_volume_size to define the sizing of root volume, in the case of azure-chroot we don't see any flag equal to these one. At Hashicorp Packer have we any solution for that? We build a linux from scratch, but this increase some complexity for our developers.

The payload names no files or tests. Begin at the azure-chroot configuration entry point and trace how its root volume is created, using the aws-chroot root_volume_size behavior as the comparison described in the issue. Done means azure-chroot provides an equivalent way to set root volume size and the behavior is verified by the project's relevant checks.

Written by the indexing model from the issue text.