Install all Python modules with setup.py; rather than copying directly with CMake

[calebmarchent]

First attempt at installation of Python modules of LogDevice was implemented by determining the dist directory, setting variable PYTHON_MODULE_INSTALL_PREFIX and then installing files into the calculated location. This method is convoluted and goes against the preferred method for packaging Python modules using distutils and setuputils.
For ldshell; we created a setup.py and then install it with a straight forward command line call:

https://github.com/facebookincubator/LogDevice/blob/2c0d9d5d9a38dfc5e60886acabc0a036eb43031e/logdevice/ops/CMakeLists.txt#L10

Switch to this method for install of all Python modules, including:

• LogDevice client binding
• Admin client
• LD Query

To find all examples search code for PYTHON_MODULE_INSTALL_PREFIX

[AhmedSoliman]

This is now done.