Find testcases by `status_issue` tag

This uses the status_issue RSpec metadata to fetch a specific issue via the API instead of searching by title/description.

• It's still possible to use JUnit reports and search via title/description
  • It will detect the file format provided via file extension
  • It will check for :status_issue metadata and if not found, it will search via title/description
• This depends on JSON-formatted test results that include status_issue (added in !503 (merged) and gitlab!38756 (merged))
• This enables JSON-formatted results and reporting for gitlab-qa pipelines, including scheduled master tests (other pipelines still to be enabled, tracked in https://gitlab.com/gitlab-org/quality/team-tasks/-/issues/504)

Part of https://gitlab.com/gitlab-org/quality/team-tasks/-/issues/504