Moved analyzer tests to its own project

Also moves tests to `./test` which makes it possible
for all test projects to share the same .editorconfig
files and similar.

test/Spectre.Console.Tests/Constants.cs

@@ -0,0 +1,21 @@
+using Spectre.Console.Cli;
+
+namespace Spectre.Console.Tests
+{
+    public static class Constants
+    {
+        public static string[] VersionCommand { get; } =
+            new[]
+            {
+                CliConstants.Commands.Branch,
+                CliConstants.Commands.Version,
+            };
+
+        public static string[] XmlDocCommand { get; } =
+            new[]
+            {
+                CliConstants.Commands.Branch,
+                CliConstants.Commands.XmlDoc,
+            };
+    }
+}