Add Baklava in Hack (#4159)

Author: rzuckerm

archive/h/hack/baklava.hh

@@ -0,0 +1,10 @@
+use namespace HH\Lib\Str;
+
+<<__EntryPoint>>
+function main(): void {
+    for ($n = -10; $n <= 10; $n++) {
+        $numSpaces = abs($n);
+        $numStars = 21 - 2 * $numSpaces;
+        echo Str\repeat(" ", $numSpaces) . Str\repeat("*", $numStars) . "\n";
+    }
+}