Allow using stdlib ssl.SSLContext with the built-in dev server

Allow using stdlib ssl.SSLContext with the built-in dev server: a task in MiMo-V2.6-RL-harbor-code: MiMo-V2.6-RL Code (Harbor) (Harbor dataset). I'm using Werkzeug's built-in dev server to do local HTTPS testing (debugging an OAuth redirect flow that requires https:// ). Since I'm on Python 3…