Add entrypoint for md2conf

This change would make it so md2conf can be installed as a script using a tool like pipx.

With this change, while in a virtual environment, the md2conf command will also be available while that venv is activated.
Likewise, when installing into a system interpreter, the md2conf command will also be made available.

For example,

# install based on my branch in my fork
pipx install git+https://github.com/AdamGagorik/md2conf.git@patch-1

md2conf --help
usage: md2conf [-h] [-d DOMAIN] [-p PATH] [-u USERNAME] [-a APIKEY] [-s SPACE] [-l {debug,info,warning,error,critical}]
               [-r ROOT_PAGE] [--generated-by GENERATED_BY] [--no-generated-by] [--ignore-invalid-url] [--local]
               mdpath
...

Assuming this PR is accepted, the command simplifies.

pipx install https://github.com/hunyadi/md2conf.git
md2conf --help

Assuming the package is then published to pypi...

pipx install markdown-to-confluence
md2conf --help

At any point in the above commands, to remove the script:

pipx uninstall markdown-to-confluence

hunyadi / md2conf

Add entrypoint for md2conf #31