vcsim: untangle container/VM to allow reuse of container logic for hosts

Refactors the container logic out of the simulator VM file so it can be
used for both VM and host container backings.

The following file structure is now in place:
* container.go - wraps docker operation execs
* container_virtual_machine.go - orchestration of containers for VMs
* container_host_system.go - orchestration of containers for Hosts
* container_xxx_test.go - test for container backed VMs/Hosts

Add CGO_ENABLED=1 to test command with -race

Makefile

@@ -136,7 +136,7 @@ endif
 
 .PHONY: go-test
 go-test: ## Runs go unit tests with race detector enabled
-	GORACE=$(GORACE) $(GO) test \
+	GORACE=$(GORACE) CGO_ENABLED=1 $(GO) test \
   -count $(TEST_COUNT) \
   -race \
   -timeout $(TEST_TIMEOUT) \