After introducing NodeFeatureRule we packed two CRD definitions in one
yaml file. Our e2e-tests were not prepared to that and the file itself
was also renamed so it couldn't even be read by the test suite.
With this change the e2e-tests start to create NodeFeatre CRD in the
test cluster, preparing for the addition of e2e-tests for NodeFeature
API.
Add tests covering the basic functionality of NodeFeatureRule objects,
covering different feature types ("flag features", "attribute features"
and "instance features") as well as backreferencing (using the output of
previously run rules) and templating. The test relies on the "fake"
feature source and its default configuration.
