Reinstate lladser_ci with improved handling of ci Results

[ChrisKeefe]

Improvement Description
lladser_ci was removed in #286 as an expedient bugfix, and should be reinstated (in q2-diversity-lib) with proper handling of its unique parameters.

@gregcaporaso suggested "maybe this should be a new top-level action in q2-diversity, probably with it’s own semantic type for the output (e.g., SampleData[AlphaDiversityConfidenceInterval])".

Creation of a new semantic type for CI metrics would allow us to prevent users from passing these results into inappropriate downstream methods, and may support how we handle #183.