Use instrumented classes in Usage Ping

Use instrumentation classes defined in metrics definitions and usage_data.rb to build the Usage Ping Payload

This will allow us use instrumentation classes for a limited type of metrics. See &6118 (closed) for adding more support

Proposed roadmap

1. add add_metric(instrumentation) method to usage_data.rb
2. Use the existing instrumentation classes in usage_data.rb
3. overite add_metric(instrumentation) in usage_data_queries.rb in order to continue support for generating metrics queries
4. overite add_metric(instrumentation) for naming suggestions in order to continue support for metrics suggestions
5. overite add_metric(instrumentation) for lib/gitlab/usage_data_non_sql_metrics.rb to continue support for non SQL metrics API

Testing considerations:

Metrics migrated to instrumentation classes in usage_data.rb:

• uuid
• hostname
• counts.issues
• count.boards
• usage_activity_by_stage.plan.issues
• usage_activity_by_stage_monthly.plan.issues

• Ensure JSON payload generated with SubmitUsagePingService is generating without any errors.
• Correspondent RawUsageData is created correctly
• Payload is submitted to version app

  RawUsageData.count
  SubmitUsagePingService.new.execute
  RawUsageData.count
  
  # inspect payload
  payload = RawUsageData.last.payload
  payload['uuid']
  payload['hostname']
  payload['counts']['issues']
  payload['counts']['boards']
  payload['usage_activity_by_stage']['plan']['issues']
  payload['usage_activity_by_stage_monthly']['plan']['issues']

• Ensure we can generate the metrics queries bundle exec rake gitlab:usage_data:dump_sql_in_yaml
• Ensure non SQL usage data is working correct Gitlab::UsageDataNonSqlMetrics.uncached_data
• Name suggestions are correct: Gitlab::Usage::Metrics::NamesSuggestions::Generator.generate("counts.boards")