Expose code intel usage stats via GraphQL

Created by: efritz

Expose the data from GetCodeIntelUsageStatistics via GraphQL.

Sample query:

{
  site {
    codeIntelUsageStatistics(days: 1, weeks: 1, months: 1) {
      daily {
        startTime
        hover {
          precise {
            usersCount
            eventsCount
            eventLatencies {
              p50
              p90
              p99
            }
          }
          fuzzy {
            usersCount
            eventsCount
            eventLatencies {
              p50
              p90
              p99
            }
          }
        }
      }
    }
  }
}