GraphQL: Add user fields to pipeline

What does this MR do?

This is MR 1/2 for #223261 (closed)

• Adds user field to PipelineType
• Adds email and status fields to UserType
• Adds a new UserStatusType with message_html, message, and emoji fields so the frontend can use it with status_tooltip_html

Screenshots

query {
  project(fullPath: "gitlab-org/gitlab-shell") {
    pipeline(iid: 17) {
      user {
        name
        avatarUrl
      	email	
        username
        webPath
        status {
          emoji
          message
          messageHtml
        }
      }
    }
  }
}

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

#223261 (closed)