feat(util): add basic trie datastructure

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
feat(util/trie): add merge method

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
feat(util/trie): add for_each and display methods

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
feat(util/trie): add for_each and display methods