feat(codegen): support multi-validators

* rename force_wrap to force
* add a bunch of builder methods to Term<Name>
* refactor one tiny location to show off builder methods
* split generate into `generate` and `generate_test`
* create wrap_as_multi_validator function

Co-authored-by: Kasey White <kwhitemsg@gmail.com>

examples/acceptance_tests/script_context/validators/basic.ak

@@ -4,8 +4,8 @@ use aiken/transaction.{NoDatum, ScriptContext, Spend, TransactionId}
 use aiken/transaction/credential.{VerificationKeyCredential}
 use aiken/transaction/value
 
-validator spend {
-  fn(_datum: Void, _redeemer: Void, ctx: ScriptContext) {
+validator {
+  fn spend(_datum: Void, _redeemer: Void, ctx: ScriptContext) {
     [
       assert_id(ctx.transaction),
       assert_purpose(ctx.purpose),