Feature: Add Citation.cff for better referencing

[Anselmoo]

Feature Description

GitHub Citation.cff helps that repos can be faster and easier cited. Adding a Citation.cff will easily allow to make use of this feature:

Reference: https://github.com/tensorflow/tensorflow

Code Example

cff-version: 1.2.0
message: "If you use TensorFlow  ...

Reason

Consistent citing with DOI

See also: https://docs.github.com/en/repositories/managing-your-repositorys-settings-and-features/customizing-your-repository/about-citation-files

Solution

Adding a CITATION.cff