WIP Poc rm flatten urls

[asmacdo]

This POC is on top of some @jortel work to flatten distributions.

Done:
(1) Flatten the url structure
(2) Removes some of the dead code
(3) Briefly tested with GET requests only

TODO:
(1) Test with POST, PUT, DELETE
(2) Rework urls.py to remove the fancy nesting tree

Here is the new Schema view from v3/
https://pastebin.com/GVma5jb4

[asmacdo]

Closing POC, this work is done in #3237