Merge branch 'stkerr-metrics-updates' into 'master'

Usage metrics update for Manage

See merge request gitlab-org/gitlab!68280

config/metrics/counts_28d/20210216180814_events.yml

 ---
 data_category: optional
 key_path: usage_activity_by_stage_monthly.manage.events
-description: 
+description: Number of distinct users who have generated a manage event by month
 product_section: dev
-product_stage: 
+product_stage: manage
 product_group: group::manage
 product_category: 
 value_type: number
 status: data_available
 time_frame: 28d
-data_source: 
+data_source: database
 distribution:
 - ce
 - ee
 tier:
 - free
-skip_validation: true
+- premium
+- ultimate
 performance_indicator_type:
 - umau