Add delete_user.md to Support workflows

Why is this change being made?

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The Locked, Banned, and Blocked Accounts workflow has an exception to manually delete user accounts, but does not document the process. This MR adds a workflow to delete users and links to the new workflow.

https://gitlab.slack.com/archives/CCBJYEWAW/p1718052954458519

Author and Reviewer Checklist

Please verify the check list and ensure to tick them off before the MR is merged.

• Provided a concise title for this Merge Request (MR)
• Added a description to this MR explaining the reasons for the proposed change, per say why, not just what
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Commits

• Add more to the Dedicated capacity planning process
• Secondary engineer on RR works on maintenance and not bugs
• updating the ps roadmap
• readme update
• Revise order of NPI steps for clarity
• Update technical scheduling HB page.md
• Added section 'How to Quote'
• Update Kick off product-leadership host
• Add info about Creating list with Mart
• Fix panel in secret push protection runbook
• Fix links in Secret Detection group page
• Adding TS removal language to procurement HB page
• Update duo and duo chat urls
• Add Laptop Advance Funds Process to CES contracts page
• The process for start date changes - France
• Update secret push protection monitoring runbook with Rails section
• add-fdegier
• Update file Technical Interview timeline
• Update host for 2024-06-12 showcase
• Revert "Merge branch 'nk312-main-patch-345d' into 'main'"
• Adding new sections to the Gitlab Personas HB Page
• Clarify valid badge types for CI Catalog
• Update Calendly handbook page for support to match the new Calendly UI
• Hanbook: Fix broken link to PS Catalog
• Fix links for Engineering Hiring Practices
• Update workflow links Update workflow links in delete_user.md and reinstating-blocked-accounts.md
• Add delete_user.md Add workflow to manually delete a user. gitlab-org/gitlab#467091 (closed)

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