Revert "Merge branch 'trunk' of D:\incubator-ambari with conflicts."

This reverts commit e2fc2da45e6b392502dee2955096371cf21c3398.
AMBARI-8237 - Alerts: Provide Summary Structure On Alerts Endpoint (jonathanhurley)
AMBARI-8249. Usability: Configs Tab UI responsiveness issues (alexantonenko)
AMBARI-8254. Pig client installation failed after upgrade (aonishuk)