Introduce a stub for the remotingCLI symbol

This stub accodomates the removal of the Remoting CLI in
jenkinsci/jenkins#3838

The change does two things:
* reintroduce the symbol by providing an no-op object for it
* have some code to rewrite the JCasC yaml files without this option

pom.xml

@@ -15,7 +15,7 @@
         <revision>1.0</revision>
         <changelist>-SNAPSHOT</changelist>
         <!-- Using always very recent on purpose -->
-        <jenkins.version>2.161</jenkins.version>
+        <jenkins.version>2.165</jenkins.version>
         <java.level>8</java.level>
     </properties>
     <name>Evergreen Plugin</name>

src/main/java/io/jenkins/plugins/evergreen/EvergreenCascUpdater.java

@@ -5,7 +5,12 @@
 import hudson.Extension;
 import hudson.init.InitMilestone;
 import hudson.init.Initializer;
+import hudson.model.PersistentDescriptor;
+import jenkins.model.GlobalConfiguration;
 import org.apache.commons.codec.digest.DigestUtils;
+import org.jenkinsci.Symbol;
+import org.kohsuke.accmod.Restricted;
+import org.kohsuke.accmod.restrictions.NoExternalUse;
 
 import java.io.IOException;
 import java.nio.file.Files;
@@ -55,4 +60,8 @@ static void fixFileIfNeeded(Path createAdminUserFilePath) throws IOException {
         }
     }
 
+    @Extension @Symbol("remotingCLI")
+    @Restricted(NoExternalUse.class)
+    public static class RemotingCLIEvergreenStub extends GlobalConfiguration implements PersistentDescriptor {
+    }
 }