Refactor Table Latency Metrics

Table request metrics (table latency histograms and TableReadQueryMeter/TableWriteQueryMeter) have been reorganized into a new metric bean TableRequests. The new TableRequests bean is published separately for each table on the regionserver, with the bean name including the table name and metric names within the bean simplified. Beans will be cleaned up after tables leave the regionserver. Users who collect TableLatencies or table query meters will have to update metric collection to work with the new structure. For example: Old: {       "name": "Hadoop:service=HBase,name=RegionServer,sub=TableLatencies",       "modelerType": "RegionServer,sub=TableLatencies",       "tag.Context": "regionserver",       "tag.Hostname": "hostname",       "Namespace_default_table_usertable_metric_deleteTime_num_ops": 0,       "Namespace_default_table_usertable_metric_deleteTime_min": 0,       "Namespace_default_table_usertable_metric_deleteTime_max": 0,       "Namespace_default_table_usertable_metric_deleteTime_mean": 0,       ... } New: {       "name": "Hadoop:service=HBase,name=RegionServer,sub=TableRequests_Namespace_default_table_usertable",       "modelerType": "RegionServer,sub=TableRequests_Namespace_default_table_usertable",       "tag.Context": "regionserver",       "tag.Hostname": "hostname",       "DeleteTime_num_ops": 0,       "DeleteTime_min": 0,       "DeleteTime_max": 0,       "DeleteTime_mean": 0,       ... }