KAFKA-12658: Include kafka-shell jar and dependencies in release tar (#10531)

Verified that `./bin/kafka-metadata-shell.sh --help` on the release tarball
works as expected. It failed with a `ClassNotFoundException` before this
change.

Reviewers: Chia-Ping Tsai <chia7712@gmail.com>, Gwen (Chen) Shapira <cshapi@gmail.com>

build.gradle

@@ -957,6 +957,8 @@ project(':core') {
     from(project.siteDocsTar) { into("site-docs/") }
     from(project(':tools').jar) { into("libs/") }
     from(project(':tools').configurations.runtime) { into("libs/") }
+    from(project(':shell').jar) { into("libs/") }
+    from(project(':shell').configurations.runtime) { into("libs/") }
     from(project(':connect:api').jar) { into("libs/") }
     from(project(':connect:api').configurations.runtime) { into("libs/") }
     from(project(':connect:runtime').jar) { into("libs/") }