Can not include Cortex python client as a requirement to the predictor

[vishalbollu]

Description

Deployments having a dependency on the cortex python package in PyPI (e.g. including cortex in requirements.txt) will fail to initialize because the the cortex serving code and the cortex python client share the same namespace cortex.

Name proposals

cortex_server
cortex_internal

Steps to reproduce

1. Deploy any API with cortex in requirements.txt

Stack traces

...
Building wheels for collected packages: cortex
  Building wheel for cortex (setup.py) ... done
  Created wheel for cortex: filename=cortex-0.23.0-cp36-none-any.whl size=30770688 sha256=7a1eb8dae84bda4c30f49595c18a239cfd63a7d9a65a99f0a83a01efbe9573d0
  Stored in directory: /tmp/pip-ephem-wheel-cache-te_8davu/wheels/f7/49/5f/095dfa4067a0e1d067b67f782cc057c0f28e6a120cd95363f2
Successfully built cortex
Installing collected packages: importlib-resources, cortex
Successfully installed cortex-0.23.0 importlib-resources-3.3.0
Traceback (most recent call last):
  File "<string>", line 1, in <module>
ModuleNotFoundError: No module named 'cortex.lib'
[cont-init.d] bootloader.sh: exited 1.
[cont-finish.d] executing container finish scripts...
[cont-finish.d] done.
[s6-finish] waiting for services.
[s6-finish] sending all processes the TERM signal.
[s6-finish] sending all processes the KILL signal and exiting.