feat: rework how modules are loaded

examples/sample/validators/swap.ak

@@ -0,0 +1,23 @@
+use sample
+use sample/mint
+use sample/spend
+
+pub type Redeemer {
+  Buy { id: Int }
+  Sell(Int)
+}
+
+pub fn spend(
+  datum: sample.Datum,
+  rdmr: Redeemer,
+  ctx: spend.ScriptContext,
+) -> Bool {
+  let y = 2
+  let x = datum.sc.signer
+  let a = datum.sc.signer.hash
+  let b = datum.rdmr
+  when b is {
+    sample.Buy -> 1 == 1
+    sample.Sell -> 5 == 1
+  }
+}