xSQLServerSetup: Add a simple integration test

[johlju]

Details of the scenario you tried and the problem that is occurring:
To start off somewhere, with integration tests, I'm working on a simple integration test for this resource. I call it simple, because this resource has a lot of aspects when looking at integration tests, and some are limited to what we can do in AppVeyor. But the more complex integration test scenarios should be able to run locally on multiple servers.
But let's create separate issues per integration test scenario, and keep this first one to a simple local single server install.

The DSC configuration that is using the resource (as detailed as possible):
n/a

Version of the Operating System, SQL Server and PowerShell the DSC Target Node is running:
n/a

What module (SqlServer or SQLPS) and which version of the module the DSC Target Node is running:
n/a

Version of the DSC module you're using, or 'dev' if you're using current dev branch:
Dev