feat(library/data/empty): add false.to_empty and false.rec_type theorems

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
feat(library/data/category): add category theory

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
feat(library/data/category): add vector

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>