Provide method of easily running local server

[Jhsmit]

Currently users have to 1) run local_cluster and 2) $ python panel/serve.py

This is a) not described in the docs in any detail and b) needs to be simplified.

[Jhsmit]

We need a console script:

entry_points={
    'console_scripts': ['<name> = <name>.console:main'],
},

https://stackoverflow.com/questions/57453047/how-to-add-command-line-tool-to-python-package

[Jhsmit]

Command to run PyHDX should be

 $ pyhdx serve 

Optional arguments:

 $ pyhdx serve --cluster 127.0.0.1:52123

Start pyhdx with existing dask cluster at '127.0.0.1:52123'

 $ pyhdx serve --cluster auto

Automatically start a cluster at a random port

[Jhsmit]

fixed by #191