Venafi-vcert-gitlab-integration

**This is a new minor release with non-breaking changes!**

- The Quay repository is renamed for better compatibility.
- Fixed the log4shel vulnerability that was caused by the VCert library (bumped to 15.2).
- Moved from Python 3.8 to python 3.9 using the slim container image
- Updates various other python libraries.
- Rebranding from Fullstaq to Qensus for compliance reasons.

**This is a new major release with breaking changes!**

Breaking changes:

* Requires pip >= 20.2.
* Renames `CLOUD_API_KEY` to `VENAFI_AS_A_SERVICE_API_KEY`, consistent with Venafi Cloud's rebranding to Venafi as a Service.
* When using Venafi as a Service, the `ZONE_CONFIG_NAME` parameter must now be in the new "Application\API Alias" syntax. The old UUID-based syntax is no longer supported. Closes 4.
* When using TPPs, we now require an API Application Integration to be setup. Learn more in the README.
* `TPP_BASE_URL` must not contain the `/vedsdk` suffix path anymore. Before: `https://tpp.venafidemo.com/vesdk`, after: `https://tpp.venafidemo.com`

Non-breaking changes:

* When using TPPs, we now use the new token authentication mechanism. This is because the classic authentication mechanism will soon be deprecated. Closes 3.
* Upgrades vcert-python to 0.11.2.

* Sets 'Origin' field in API calls, so that Venafi can see which integration is responsible for the API calls.
* Fixes a typo in the README: RENEWAL_WINDOW should be EXPIRATION_WINDOW.

Adds a feature for skipping certificate renewal when it's recent enough. See the README, section "Renewing certificate only when expiration is near".

Initial release.