move kitchen-sink demo into a separate directory

demo/kitchen-sink/docs/powershell.ps1

@@ -0,0 +1,24 @@
+# This is a simple comment
+function Hello($name) {
+  Write-host "Hello $name"
+}
+
+function add($left, $right=4) {
+    if ($right -ne 4) {
+        return $left
+    } elseif ($left -eq $null -and $right -eq 2) {
+        return 3
+    } else {
+        return 2
+    }
+}
+
+$number = 1 + 2;
+$number += 3
+
+Write-Host Hello -name "World"
+
+$an_array = @(1, 2, 3)
+$a_hash = @{"something" = "something else"}
+
+& notepad .\readme.md