Add test case for multiple channels on one connection + remove integr…

…ation tests in `_test` (#1021)

* test: add multiple channels on one connection test case via ibctest

* chore: remove old docker integration test make cmds

* chore: remove github CI actions for old docker integration tests

* chore: remove `_test` directory containing the old docker integration tests

Makefile

@@ -54,18 +54,6 @@ build-osmosis-docker:
 test:
 	@go test -mod=readonly -race ./...
 
-test-integration:
-	@go test -mod=readonly -v -timeout 20m ./_test/
-
-test-gaia:
-	@go test -mod=readonly -v -run 'TestGaiaToGaiaRelaying|TestGaiaToGaiaRelaying|TestUnorderedChannelBlockHeightTimeout|TestUnorderedChannelTimestampTimeout' ./_test
-
-test-akash:
-	@go test -mod=readonly -v -run TestAkashToGaiaRelaying ./_test/
-
-test-short:
-	@go test -mod=readonly -v -run TestOsmoToGaiaRelaying ./_test/
-
 ibctest:
 	cd ibctest && go test -race -v -run TestRelayerInProcess .