Added pagination support to the networks page under
Project and Admin Dashboard.
To accomplish so, the method network_list_for_tenant
in api/neutron.py that is used for listing networks under
the Project Dashboard was refactored to merge the different
requests for shared, non-shared and external networks while
tracking the pagination for each of those requests, so for
instance when all the shared networks are listed and paginated
then the non-shared networks are queried and so on.
For the Admin dashboard all network types are retrieved under
a single request so it is a simpler pagination logic.
Partial-Bug: #1746184
Change-Id: I96a2d6cabed47c89bdc02ec922d7f9451e5ec025
196de449b6