Provide hex representation of message hash

[vpavlin]

This is a feature request

Problem

message-hash package currently provides the hash in a form of byte array or string, it would be useful if it also allowed to obtain the msg has in the form of hex (0x...) to match representation logged in other clients like nwaku

messageHashStr output :

��.t����������`j�ɷ���[��3z��.r�

Proposed Solutions

Provide messageHashHex method returning the hash like

0x9c632f9cfb98aea3801545ba899791592cd7c37240143777fab489443c777300

This will make it easier to identify messages accros clients

Notes