adds dRNG integration test

.../drng/subtypes/collectiveBeacon/collective_beacon_test.go

tools/integration-tests/tester/data/client-script.sh

tools/integration-tests/tester/framework/docker.go

tools/integration-tests/tester/framework/drand.go

tools/integration-tests/tester/framework/drngnetwork.go

tools/integration-tests/tester/framework/framework.go

tools/integration-tests/tester/framework/network.go

tools/integration-tests/tester/framework/parameters.go

tools/integration-tests/tester/framework/peer.go

tools/integration-tests/tester/framework/util.go

tools/integration-tests/tester/go.mod

tools/integration-tests/tester/tests/drng_test.go