[Experiment][Compute] New-AzVm should create a strorage account

[sergey-shandar]

The issues is that a storage account has to be created in the same location. By default, Azure tries to reuse an existing storage which could be in a different location.

• by default, boot diagnostic should be disabled
• if boot diagnostic is required, then storage account should be provided.

[sergey-shandar]

The storage account is created for Boot Diagnostics only.