Summary:
All external libraries now automatically include their include directories. It
is necessary only to link to the external library using
`target_link_libraries(target library)` and the include directory of the
library will be automatically available for the binary.
Reviewers: teon.banek
Reviewed By: teon.banek
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2654