Add prelude and while macro

This commit introduces a new prelude file that defines the `while` macro
and registers it during environment bootstrapping. The `again` macro has
been updated to accept multiple arguments for its recursive call, and
several examples have been adjusted to reflect this change.
Additionally, the `MacroRegistry` in the compiler is now cloneable and
can be moved out of the `MacroExpander`.

examples/again.myc

@@ -1,10 +1,10 @@
-;; Benchmark: 2.5us
-;; Benchmark-Repeat: 804
+;; Benchmark: 2.5us
+;; Benchmark-Repeat: 804
 ;; Output: 120
 (do
   (def factorial (fn [n acc]
     (if (= n 0)
       acc
-      (again [(- n 1) (* acc n)]))))
+      (again (- n 1) (* acc n)))))
 
   (factorial 5 1))