Fix @property regressions introduces by UDA module update

Recent change to `findFirstUDA` has introduced a regression in a way that symbol of property function used for attribute got captured into result instead of returned value. This fixes it and also makes `isPropertyGetter/Setter` tiny bit more versatile.

Also:
1) fixes rest test suite to stop referring removed module
2) public import of `before` and `after` from `vibe.http.rest`