Add typing, some refactor, run and fix all doctests

[artemisart]

• type type type many things
• doctests were not run ! fixed all doctests, there were many errors
• make outer join follow the input ordering (avoids sets)
• factorise & reuse some methods -> we can remove the implementation of distinct, select, where, order_by, flatten, zip_with_index, init
• remove PRE_COMPUTE by doing the lists in the functions where needed
• simplify some counters, group by operations
• fix some exception types (ValueError that should be TypeError, ...)

TODO potential improvement: improve typing on _wrap returns like __getitem__

[maestro-1]

Don't you think the changes in this might be too much to push all at once?