Move Integration Tests with Reqnroll to use NUnit

[StuartFerguson]

Add this to the test project AssemblyInfo.cs to control parallel testing

[assembly: LevelOfParallelism(2)]
[assembly: Parallelizable(ParallelScope.Fixtures)]

[StuartFerguson]

Add the following locking code to prevent Sql Server container errors during concurrent tests GlobalSetup method

// Only one thread can execute this block at a time
lock (Setup.padLock)
{
Setup.DatabaseServerNetwork = dockerHelper.SetupTestNetwork("sharednetwork");

dockerHelper.Logger.LogInformation("in start SetupSqlServerContainer");
Setup.DatabaseServerContainer = dockerHelper.SetupSqlServerContainer(Setup.DatabaseServerNetwork).Result;
}

static object padLock = new object(); // Object to lock on