Move to poetry

[qkaiser]

This MR migrate ubi-reader from setuptools to Poetry and setup a CI job to release to PyPi using our token.

The README has been updated accordingly. The documentation will be fully updated when we work towards establishing our baseline, with explanation on how to install Poetry / setup dev environment.

[wh201906]

I think this PR breaks the compatibility for scripts using setup.py. It should be kept.
For example:
https://github.com/ReFirmLabs/binwalk/blob/cddfede795971045d99422bd7a9676c8803ec5ee/deps.sh#L116-L121

[vlaci]

I'd be happier if noone would depend on pacakges having setup.py anymore. It is a deprecated practice for over two years. The correct way to install this project is to call pip similarly to how install_pip_package does a couple of lines below in the cited example.

[wh201906]

Hopefully other projects using this module will switch to the new install methods.