Summary:
Knowledge of distributed operators is now removed from PlanPrinter
class. The DistributedOperatorVisitor and PlanPrinter are modified so
that they may be multiple inherited. This is done using virtual
inheritance of HierarchicalLogicalOperatorVisitor. Multiple inheritance
is used to derived a DistributedPlanPrinter which knows how to print
distributed in operators. This removes the dependency of single node
pretty printing on distributed.
Reviewers: msantl, mtomic
Reviewed By: mtomic
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1606
e67fc40743