Introduce versioning

[Cierpliwy]

We need to come up with a strategy to introduce versioning shortly. Currently, a lot of names and features are unstable, and we should communicate than through versioning. I can see the following steps required to achieve it:

• Define the versioning scheme in the README file.
• Add changelog, when breaking changes are introduced.
• Create release packs with bundled CMake files (should be a Github Action triggered by tags).