Not working dpCtl API documentation

[akharche]

Tried to build documentation based on provided instructions. Several problems were detected:

1. I can not install package exhale via pip or conda. Conda pckgs are not provided, pip gives the error:
   ERROR: Could not find a version that satisfies the requirement exhale
2. The command line in the documentation does not work:
   mkdir build cd build cmake -DDPCTL_DOCGEN_PREFIX=<WHERE_YOU_WANT_DOCS_TO_BE_GENERATED> make Sphinx
   Changes to:

mkdir build cd build 
cmake .. -DDPCTL_DOCGEN_PREFIX=<WHERE_YOU_WANT_DOCS_TO_BE_GENERATED>
make

And it fails due to missing exhale package

[diptorupd]

@akharche I managed to get exhale (https://pypi.org/project/exhale/) from pip.

[akharche]

@diptorupd After several tries I've found that something wrong with my conda environment and pip failed to install any package.

[diptorupd]

@akharche can we close this ticket?

[akharche]

#226