Add input wordlist functionality

[denandz]

This pull request adds the ability to pass pencode an input wordlist, rather than only accepting input via stdin.

The use case here is when fuzzing something like a JSON or SOAP API with predefined wordlists and ffuf/intruder/whatever. I'd like to be able to pass my attack wordlist to pencode directly, and have it spit out the encoded/escaped versions of the payloads that I can subsequently use to fuzz a specific target without unintentionally breaking the JSON/XML encoder.

[denandz]

Hey @joohoi any blockers to getting this merged? Also fixes issue #34 by providing an option to read items from an existing wordlist line-by-line.

[joohoi]

Thanks for the ping, and sorry for the late response. No, this looks good. I'm also working on a proper integration of pencode to ffuf itself.

With the integration you will be able to give ffuf a parameter like -encode "FUZZ:b64encode somethingelse templatefile"

[denandz]

All good! Thanks Joohoi.