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/Expectations/Cli/Help/Leaf.Output.verified.txt

@@ -0,0 +1,9 @@
+USAGE:
+    myapp cat [LEGS] lion <TEETH> [OPTIONS]
+
+ARGUMENTS:
+    <TEETH>    The number of teeth the lion has
+
+OPTIONS:
+    -h, --help       Prints help information
+    -c <CHILDREN>    The number of children the lion has