Move tests which depends on external service (metering test) into integration test package

[vsbogd]

Following up #518.

As metering tests depend on external server (see https://github.com/singnet/snet-daemon/pull/515/files) they should be moved into separate package, lets say integration_test and removed from unit test chain. They should be started manually before release or by CI in separate environment. They cannot be used as unit tests as they cannot be built offline.

Also see #448

[anandrgitnirman]

#429