Test registration automation

[peinjoh]

As @oxisto mentioned in #186, adding a test requires the manual update of

csaf/csaf-rs/src/csaf2_0/validation.rs

Line 9 in a051c6f

let basic_tests = Vec::from(["6.1.1", "6.1.2"]);

and

csaf/csaf-rs/src/csaf2_1/validation.rs

Line 18 in a051c6f

let basic_tests = Vec::from([

Doing this manually is cumbersome and error-prone.

In the same vein, @tziemek added a list to track the implementation status of the tests in the README.md (#176). The same applies here.

We should look into filling these automatically via a macro/script.