Summary:
With this diff we should be able to support dynamic worker addition.
This is ofcourse a minimal effort maximal impact approach.
This diff introduces new RPC calls when a worker registers.
The `DynamicWorkerAddition` doesn't use `GraphDbAccessor` to get indices because
they create WAL entries.
Reviewers: vkasljevic, ipaljak, buda
Reviewed By: ipaljak
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D1594