Summary:
- Aggregation LogicalOperation added, with tests.
- Added capabilities to TypedValue (hash, bool-equality)
to support std::unordered_map<TypedValue>.
- Removed some bad code from utils/hashing/fnv and added
a hashing function for collections.
Reviewers: buda, mislav.bradac, teon.banek
Reviewed By: teon.banek
Subscribers: lion, pullbot
Differential Revision: https://phabricator.memgraph.io/D252
