Rethink and rewrite datomic schema inferencing

[aamedina]

Problem:

Right now there are multimethods used to navigate the metaobject type hierarchy and while this works I find it cumbersome to write and reason about.

Solution:
Instead I think the user interface needs to be EDN that expands into multimethod implementations and "hide" the multimethods from the user. The hierarchical dispatch can still be useful. Another possibility is adding an interactive mode where if a schema attribute is ambiguous the user will be prompted to disambiguate.