Remove Database Engineering Allocation policy

What does this MR do and why?

Describe in detail what your merge request does and why.

Removes the Engineering Allocation automation for groupdatabase as they are moving off of 100% Engineering Allocation : gitlab-com/www-gitlab-com!100753 (merged) and this helps ensure Eng Allocation metrics are accurate

Expected impact & dry-runs

These are strongly recommended to assist reviewers and reduce the time to merge your change.

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