feat(production backend dockerfile) & enhanced(backend deps) & fix(userInfo bugs)

• Dropped the use of Pandas & updated loading scripts accordingly

• Separated python requirements files

• Updated Dockerfile to be able to also build a production ready image (without dev dependencies)

• Backend images size cut in more than half 🎉

• Updated a bit the documentation related to Docker

• CI now depends on clear image tags

• Fixed the serializers of User and enhanced frontend of userinfo

• Fixed wrong compose in frontend

Fixes #108 (closed) #109 (closed) #104 (closed) Linked to #66 (closed) for new prod dockerfile