yaml-validator-cli should include samples and error tests using the new anyOf/oneOf/allOf schema

[MathiasPius]

There are already tests for the functionality in the library, but there are no examples using them in the yaml-validator-cli project yet.

Error message formatting is very important to get right for these, as they are otherwise impossible to debug.

[MathiasPius]

Partially solved in https://github.com/MathiasPius/yaml-validator/pull/33/files but only for allOf