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/Data/Settings/ArgumentOrderSettings.cs

@@ -0,0 +1,22 @@
+using Spectre.Console.Cli;
+
+namespace Spectre.Console.Tests.Data
+{
+    public sealed class ArgumentOrderSettings : CommandSettings
+    {
+        [CommandArgument(0, "[QUX]")]
+        public int Qux { get; set; }
+
+        [CommandArgument(3, "<CORGI>")]
+        public int Corgi { get; set; }
+
+        [CommandArgument(1, "<BAR>")]
+        public int Bar { get; set; }
+
+        [CommandArgument(2, "<BAZ>")]
+        public int Baz { get; set; }
+
+        [CommandArgument(0, "<FOO>")]
+        public int Foo { get; set; }
+    }
+}