[owasp-modsecurity compatibility] base64Encode method

[tty2]

Summary

coraza doesn't implement method base64Encode
owasp-modsecurity has this method

Basic example

https://github.com/owasp-modsecurity/ModSecurity/wiki/Reference-Manual-(v3.x)#user-content-base64Encode

Motivation

OWASP modsecurity compatibility

[fzipi]

Thanks for reporting! Are you up for a PR?

[tty2]

Hi @fzipi
I'm gonna take it to implement soon
Just need to spend time to make sure if we should use std lib or make something else like in decode implementation?
If you already have knowledge that std encoding doesn't work here, please share it.

[tty2]

Implemented with #1257