[Ceres]: Add arbitrary size byte arrays (#456)

* Extend compiler to allow bytes()/bytes as type

* Add split_any, to_fixed_size, size, to_any_size, Int.to_bytes and String.to_bytes

* Add tests

* Use and and not andalso in unify, some things have side-effects

* Bump to aebytecode v3.3.0

* Changelog + update documentation

* fix wording in documentation

test/contracts/bytes_to_x.aes

@@ -6,3 +6,5 @@ contract BytesToX =
     String.concat(Bytes.to_str(b), Bytes.to_str(#ffff))
   entrypoint to_str_big(b : bytes(65)) : string =
     Bytes.to_str(b)
+  entrypoint to_fixed(b : bytes()) : option(bytes(4)) = Bytes.to_fixed_size(b)
+  entrypoint to_any(b : bytes(4)) = Bytes.to_any_size(b)