Allow File Redirection in WasmerJS

[torch2424]

Should be done in wasmer js

https://unix.stackexchange.com/questions/122977/what-is-the-correct-name-for-the-command

E.g echo "a" > x.txt

[torch2424]

In Wasmer JS as: https://github.com/wasmerio/wasmer-js/issues/95