discover mongodb via discovery service, not dns

...asapo_discovery/request_handler/request_handler_consul.go

..._discovery/request_handler/request_handler_consul_test.go

...asapo_discovery/request_handler/request_handler_static.go

..._discovery/request_handler/request_handler_static_test.go

discovery/src/asapo_discovery/server/get_receivers.go

discovery/src/asapo_discovery/server/listroutes.go

discovery/src/asapo_discovery/server/routes_test.go

discovery/src/asapo_discovery/server/settings_test.go

receiver/src/receiver_config.cpp

receiver/src/receiver_config.h

receiver/src/receiver_error.h

receiver/src/request_handler_db.cpp

receiver/src/request_handler_db.h

receiver/src/request_handler_db_meta_write.cpp

receiver/src/request_handler_db_write.cpp

receiver/src/statistics_sender_influx_db.cpp

receiver/unittests/mock_receiver_config.cpp

receiver/unittests/test_config.cpp

receiver/unittests/test_request_handler_db.cpp

receiver/unittests/test_request_handler_db_meta_writer.cpp