RemoteLinux: Make build/deploysteps constructible by id only

Will help to remove some of the remaining hard dependencies of Qnx and
Boot2Qt on RemoteLinux.

Change-Id: I1a327249a9b2903b5b9d869cb9cd60bb50250a5c
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/remotelinux/rsyncdeploystep.cpp

@@ -26,6 +26,7 @@
 #include "rsyncdeploystep.h"
 
 #include "abstractremotelinuxdeployservice.h"
+#include "remotelinux_constants.h"
 
 #include <projectexplorer/deploymentdata.h>
 #include <projectexplorer/runconfigurationaspects.h>
@@ -211,7 +212,7 @@ RsyncDeployStep::~RsyncDeployStep() = default;
 
 Utils::Id RsyncDeployStep::stepId()
 {
-    return "RemoteLinux.RsyncDeployStep";
+    return Constants::RsyncDeployStepId;
 }
 
 QString RsyncDeployStep::displayName()