Triage reports - No direct mention in description and autoclose from due date

What does this MR do and why?

Closes #1094 (closed)

Changes the reports to:

• Not directly mention people in the issue description (@a-user -> @a-user)
• Set a due_date to all reports of 1 week (used to be 2 weeks)
• Close all expired reports (i.e. when they have a due date), and continue to clean reports after two weeks in case they don't have a due date set.

Expected impact & dry-runs

Dry-run in https://gitlab.com/gitlab-org/quality/triage-ops/-/jobs/3473009253.

From the samples I took in the issues it would close, it would close reports with an expired due date or the ones that have been created at least two weeks ago ✅

Action items

• (If applicable) Add documentation to the handbook pages for Triage Operations =>
• (If applicable) Identify the affected groups and how to communicate to them:
  • /cc @person_or_group =>
  • Relevant Slack channels =>
  • Engineering week-in-review