add generated PsiClass cache with CachedValuesManager + add generated class qualifiedName index

CachedValueManager is used internaly of ParseAndGenerateManager and allows us to generate the PsiClass of DAMapping generated classes/interfaces only once per PsiClass annoted with @Mapper
CachedValueManager implements refreshing cached values whenever the annoted PsiClass is modified
add an index of the annoted classes by their qualifiedName to implement PsiElementFinder.getAllClasses(Package, ...)