Chall-Manager's scenario decoding process does not check for zip slips

Chall-Manager is a platform-agnostic system able to start Challenges on Demand of a player. When decoding a scenario (i.e. a zip archive), the path of the file to write is not checked, potentially leading to zip slips. Exploitation does not require authentication nor authorization, so anyone can exploit it. It should nonetheless not be exploitable as it is highly recommended to bury Chall-Manager deep within the infrastructure due to its large capabilities, so no users could reach the system. Patch has been implemented by commit 47d188f and shipped in v0.1.4.