Added proxying package
Created new class ExternalRequest and made ProxiedRequest a subclass
Correcting class for Loggers
Only ProxiedRequest should need to deal with params
Rename `proxy()` in ExternalRequest as it doesn't make sense in that context
Added ProxiedRequest tests

Including some changes to ProxiedRequest and ExternalRequest
Tests for ExternalRequest
Merge pull request #785 from aodn/refactor_proxied_request

Refactor proxied request