Publish end-to-end tests as a standalone executable

[damonbarry]

• Remove unused using statements
• When installing IoT Edge from snaps, alias the iotedge CLI
• Remove no-longer-needed abstraction for executing iotedge CLI commands in the tests
• Add Ubuntu Core as a supported distro in end-to-end tests
• Migrate from NUnit to MSTest
  • [EndToEnd] attribute becomes [TestClass] + [TestCategory("EndToEnd")]
  • [Test] attribute becomes [TestMethod]
  • [Category("...")] attributes become [TestCategory("...")]
  • [Values] attributes become [DataRow(...)] attributes
  • In DataRow tests, add test arguments as a custom "Row" property to TestContext so we can output the full test name in our custom logging
  • Assert.NotNull(...) becomes Assert.IsNotNull(...)
  • Assert.Ignore(...) becomes Assert.Inconclusive(...)
  • Assert.That(...) has no analog in MSTest, but StringAssert.StartsWith(...) does what we need in the one case where we used Assert.That(...)
  • Assert.Zero(...) becomes Assert.AreEqual(0, ...)
  • Use in the CSPROJ file
  • [OneTimeSetup]/[OneTimeTearDown] becomes [AssemblyInitialize]/[AssemblyCleanup]
  • AssemblyInitialize/AssemblyCleanup methods must be static, so convert to static any class members we manage within those methods
  • [OneTimeSetUp]/[OneTimeTearDown] becomes [ClassInitialize]/[ClassCleanup]. Use [ClassInitialize(InheritanceBehavior.BeforeEachDerivedClass)] so inherited init methods are called too (similar to NUnit)
  • ClassInitialize/ClassCleanup methods must be static, so convert to static any class members we manage within those methods
  • [SetUp]/[TearDown] becomes [TestInitialize]/[TestCleanup]
• We can't easily install libicu on Ubuntu Core, so set System.Globalization.Invariant = true in test/Microsoft.Azure.Devices.Edge.Test/runtimeconfig.template.json

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General Guidelines and Best Practices

• I have read the contribution guidelines.
• Title of the pull request is clear and informative.
• Description of the pull request includes a concise summary of the enhancement or bug fix.

Testing Guidelines

• Pull request includes test coverage for the included changes.
• Description of the pull request includes
  • concise summary of tests added/modified
  • local testing done.