Add time range arguments to AiUsageEventsResolver

What does this MR do and why?

Currently AiUsageEvents type doesn't provide any option to reduce events scope. Here we add common timestamp range filtering option to query for smaller\past timeframes. We also provide a limit of 1 month max time range.

Database review

events query

How to set up and validate locally

Try this query:

{
  group(fullPath: "gitlab-org") {
    aiUsageData {
      all {
        pageInfo {
          endCursor
          startCursor
        }
        nodes {
          event
          timestamp
          user {
            username
          }
        }
      }
    }
  }
}

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Related to #559045 (closed)