Fix publication of elasticsearch-cli to Maven

This commit addresses the publication of the elasticsearch-cli to
Maven. For now for simplicity we publish this to Maven so that it is
available as a transitive dependency for any artifacts that depend on
the core elasticsearch artifact. It is possible that in the future we
can simply exclude this dependency but for now this is the safest and
simplest approach that can happen in a patch release.

Relates #27853

core/cli/build.gradle

@@ -20,6 +20,17 @@
 import org.elasticsearch.gradle.precommit.PrecommitTasks
 
 apply plugin: 'elasticsearch.build'
+apply plugin: 'nebula.optional-base'
+apply plugin: 'nebula.maven-base-publish'
+apply plugin: 'nebula.maven-scm'
+
+publishing {
+    publications {
+        nebula {
+            artifactId 'elasticsearch-cli'
+        }
+    }
+}
 
 archivesBaseName = 'elasticsearch-cli'