build: implement a framework for starting test servers during tests

Test servers are implemented by docker containers and run real servers
for rclone to test against.

backend/swift/swift_test.go

@@ -20,7 +20,7 @@ import (
 // TestIntegration runs integration tests against the remote
 func TestIntegration(t *testing.T) {
 	fstests.Run(t, &fstests.Opt{
-		RemoteName: "TestSwift:",
+		RemoteName: "TestSwiftAIO:",
 		NilObject:  (*Object)(nil),
 	})
 }