MD5
Work with MD5 digests in Gren.
digest :
String -> String
Return the MD5 digest for a string
digest ""
--> "d41d8cd98f00b204e9800998ecf8427e"
digest "hello"
--> "5d41402abc4b2a76b9719d911017c592"
digest "æ ø å ñ"
--> "38e3f1e10c0b5072c874a72c3c6493d8"