Refactor modules to separate parsing and request engine

[cryptaliagy]

This is somewhat unrelated to this PR but given that you're refactoring I would like to see the request engine and the parser decoupled in some future refactor. I'm not sure if that was already in your plans but I think that will make each component much easier to test and maintain the future.

Originally posted by @DudeRandom21 in https://github.com/andrewnags/uoapi/pull/19#discussion_r1045305997