Use Azure Storage emulator for integration tests

[dadoonet]

If available on the machine we are running our tests (which is something we can detect by checking storageConnection system property), we can use the Azure Storage emulator to run snapshot and restore tests which are closer to the test we run today.

According to the source code and the documentation, the storageConnection should contain something like:

Account name: devstoreaccount1
Account key: Eby8vdM02xNOcqFlqUwJPLlmEtlCDXJ1OUzFT50uSRZ6IFsuFq2UVErCz4I6tq/K1SZFPTOtr/KBHBeksoGMGw==

[ywelsch]

Thanks @dadoonet, the emulator looks interesting. We'll relay this to the infra team, and check if we can make this part of our snapshot/restore integration tests. I'll close this issue here, because there's no need to track it in this repository.