WIP: better packaging

i noticed that setup.py is only used to install dependencies and nothing else. no actual code is installed. what if we cleaned up the package structure and made the code actually install as a package?

access to manage.py is done via entrypoints's console_scripts, as elixmanage. suggested goal:

$ pip install elixire
$ mkdir my_elixire_instance && cd my_elixire_instance
$ elix setup # setup folders in this directory
$ elix run # run hypercorn etc
$ elixmanage # manage instance... maybe can be elix manage?