Provide simplified IArtifactEvaluator for variability framework #1376
Description
Several use cases of working with variability artefacts require to evaluate the variation points of an artefact's AST and compute which nodes will be filtered in a 100% model. However, the variability-base implementation currently only provides a dummy IArtifactEvaluator implementation which assumes that nothing will be filtered.
An IArtifactEvaluator should be provided instead which offers basic filtering functionality. It will not support the full expressiveness of feature models and artifact variation points. Matching the restricted functionality of SkeletonTreeBaseBuilder, the following features will not be supported by the IArtifactEvaluator in variability-base:
- variability with instantiation
- logical children
- dependent sources
- presence prerequisites
- structural evaluation