feature: fetch user last success submission

[AlcibiadesCleinias]

feat: add a new command to makefile: generate-with-last-submissions (Generate back side of the card with the last accepted submission), e.g. image docs: introduce a new method, add screenshots example for cookie/session fix: optionally use csrf_token from env (it should resolve https://github.com/fspv/leetcode-anki/issues/39) refactor: improve code style a bit (sorry), and I fixed some libs that were not fixed in the requirements.txt

ps. Also, I left several new TODOs, and the feature with code submission is a kinda experiment as it is created without tests, via using a kinda closed method of leetcode-python lib, and with the help of direct parsing of that raw request.

would appreciate if someone would support the PR, for myself I did want I wanted - created Anki cards with ps. also I am opened for the comments and review