Summary:
New flags are introduced.
1) `node-label` flag can be specified multiple times to add
extra labels to all nodes
2) `relationship-type` overwrites relationship types from file
with given flag value
3) `quote` is used to specify quotation character
Added tests for new flags.
Reviewers: teon.banek, msantl
Reviewed By: teon.banek
Subscribers: mferencevic, pullbot
Differential Revision: https://phabricator.memgraph.io/D1514
