Make TropPOLoRaTools an installable package

[wtbarnes]

Currently, this piece of software represents a useful collection of scripts. However, in order to better facilitate ease of use by outside users and enable easier workflows, it may be useful to make this into an installable library. See this guide for a walkthrough of how to create installable Python packages.

[wtbarnes]

This would also greatly ease the problem of installing all needed dependencies as these could be listed in the setup.py (or setup.cfg) file and the installation handled by pip.