PenDoc vulnerable to Arbitrary File Read on updating and downloading templates using Path Traversal

PwnDoc is a penetration test report generator. Prior to commit 1d4219c596f4f518798492e48386a20c6e9a2fe6, an authenticated user who is able to update and download templates can inject path traversal (`../`) sequences into the file extension property to read arbitrary files on the system. Commit 1d4219c596f4f518798492e48386a20c6e9a2fe6 contains a patch for the issue.