fix(kernel/abstract): bug in abstract for telescopes

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
feat(kernel/inductive): add getters for inductive decls

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
feat(library/kernel_bindings): add Lua API for declaring datatypes

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