Find all and by-name Mock for Query API orgVdcNetwork

* Just for OrgVdcNetwork for now
* Be clear about what options/queries are unimplemented
* Expand tests to cover mocks
* comment to explain gnarly test logic
* :page=1 results handled
improve network mock test data, to include vdc & IsShared
fix tests for running against live environment
make Mock vcloud_director_host an FQDN
[vclouddirector] Shore up tests re EdgeGateway

ruby 1.8.7 highlighted tests fail if first vdc does not have an edge gateway
rename Mock vcloud_director_host to pass URI.parse
Merge pull request #2478 from alphagov/vcloud_director_get_execute_query_mock

Vcloud director get execute query mock