Restore hive-exec-core jar

The hive-exec-core jar is used by spark, oozie, hudi and many other pojects. Removal of the hive-exec-core jar has caused the following issues.

Spark : https://lists.apache.org/list?dev@hive.apache.org:lte=1M:joda
Oozie: https://lists.apache.org/thread/yld75ltf9y8d9q3cow3xqlg0fqyj6mkg
Hudi: apache/hudi#8147

Until the we shade & relocate dependencies in hive-exec, we should restore the hive-exec core jar .