Proxmoxer

* Bugfix (https): properly pass verify_ssl all the way to the backend auth ([Dominik Rimpf](https://github.com/domrim))

* Improvement (all): Convert testing framework to use pytest ([John Hollowell](https://github.com/jhollowe))
* Improvement (all): Remove Python 2.x support (minimum version of 3.7) ([John Hollowell](https://github.com/jhollowe))
* Improvement (all): Refactor code to Python 3 standards ([John Hollowell](https://github.com/jhollowe))
* Bugfix (all): Remove None values from request data and params ([Kristian Heljas](https://github.com/kristianheljas))
* Addition (tools): Added Task tools ([John Hollowell](https://github.com/jhollowe))
* Bugfix (all): Allow specifying resource_id as 0 ([John Bergvall](https://github.com/johnbergvall))
* Improvement (all): Remove ProxmoxResourceBase ([John Hollowell](https://github.com/jhollowe))
* Bugfix (all): Add platform detection before using shlex functions ([Kevin Boyd](https://github.com/r3d07))
* Improvement (https): Added `path_prefix` argument which is appended after the root of the URL (before `api2/`) ([John Hollowell](https://github.com/jhollowe))

Breaking Changes
* `ProxmoxResourceBase` removed
* `proxmoxer.backends.https.AuthenticationError` moved to `proxmoxer.AuthenticationError`
* Removed `ProxmoxHTTPTicketAuth` and its arguments `auth_token` and `csrf_token`
* keyword arguments to backends order changed (should not affect users specifying arguments by name)

* Bugfix (all): fix error handling for APIs that don't give a dict in the response ([Alex Wuillaume](https://github.com/wuillaumea))

* Addition (local): Added `local` backend for running directly on Proxmox hosts. ([Markus Reiter](https://github.com/reitermarkus))
* Bugfix (all): properly parse command string sent to QEMU guest agent ([John Hollowell](https://github.com/jhollowe))
* Improvement (command_base): Refactor code to have a unified CLI backend base for `openssh`, `ssh_paramiko`, and `local` backends ([Markus Reiter](https://github.com/reitermarkus))
* Improvement (https): Support IPv6 addresses ([Daviddcc](https://github.com/dcasier))
* Improvement: Move CI to GitHub actions from Travis.ci ([John Hollowell](https://github.com/jhollowe))
* Improvement: Cleanup documentaiton and move to dedicated site ([John Hollowell](https://github.com/jhollowe))
* Improvement: Add `pre-commit` hooks for formatting and linting and format all code ([John Hollowell](https://github.com/jhollowe))

* Addition (https): Added OTP code support to authentication ([John Hollowell](https://github.com/jhollowe))
* Addition (https): Added support for large file uploads using requests_toolbelt module ([John Hollowell](https://github.com/jhollowe))
* Addition (all): Added support for Proxmox Mail Gateway (PMG) and Proxmox Backup Server (PBS) with parameter validation ([Gabriel Cardoso de Faria](https://github.com/gabrielcardoso21), [John Hollowell](https://github.com/jhollowe))
* Addition (all): Added detailed information to ResourceException ([mihailstoynov](https://github.com/mihailstoynov))
* Bugfix (base_ssh): Resolved issue with values containing spaces by encapsulating values in quotes ([mihailstoynov](https://github.com/mihailstoynov))
* Bugfix (all): Resolved issue with using get/post/push/delete on a base ProxmoxAPI object ([John Hollowell](https://github.com/jhollowe))
* Bugfix (all): Added support for responses which are not JSON ([John Hollowell](https://github.com/jhollowe))
* Improvement: Added and updated documentation ([Ananias Filho](https://github.com/ananiasfilho), [Thomas Baag](https://github.com/b2ag))
* Improvement: Tests are now not installed when using PIP ([Ville Skyttä](https://github.com/scop))
* Addition: Devcontainer definition now available to make development easier ([John Hollowell](https://github.com/jhollowe))

* Bugfix (https): correctly renew ticket in the session, not just the auth ([John Hollowell](https://github.com/jhollowe))