Backporting Bug#25423650: QUICK UNINSTALL PLUGIN WHILE START GR CAN RESULT INTO DEADLOCK

Issue:
======
when executing 'select * from
performance_schema.replication_connection_status' concurrently with
"stop group_replication", both gets stucked.

Resolution:
===========
Group_replication_handler class has been removed along with
lock LOCK_group_replication_handler.
With use of my_plugin_lock_by_name, server will have better visibility over
GR operations and take decisions accordingly.