[Other] Add release upload to Zenodo for DOI registration and `CITATION.cff` file

Is there an existing issue for this?

[X] I have searched the existing issues

Current State & Issue

Considering Kipper is a partially scientific project (coming from HTL Leonding and likely soon working with the JKU in Linz) adding a CITATION.cff file would help allow other people to cite the project as well as properly understand who worked when on the project in a more formal way than with standard repository info.

Alongside this using Zenodo would also be rather beneficial to officially allow the project to get a DOI, which can distinguish it from other projects and help it gain more credibility.

Proposed Changes

[x] Add a new CITATION.cff file based on the format given here https://citation-file-format.github.io/
[x] Set up Zenodo release upload to allow for version-specific DOI assignment
[x] Add Zenodo DOI badge for the latest release to the README.md files of every sub-project.

Kipper-Lang / Kipper