Provide an installable python package

[git-developer]

This PR adds metadata to simplify the installation and start of joycond-cemuhook.

Examples for installation:

# install latest commit of the default branch
pip3 install git+https://github.com/joaorb64/joycond-cemuhook

# install from branch `develop`
pip3 install git+https://github.com/joaorb64/joycond-cemuhook@develop

# install from master branch without git
pip3 install https://github.com/joaorb64/joycond-cemuhook/archive/master.zip

To start, just run joycond-cemuhook in any directory.

May be tested using repo https://github.com/git-developer/joycond-cemuhook and branch feature/python-package

[git-developer]

References #71.