Update redirects due Jul2021

For technical-writing#447 (closed)

• ./doc/administration/git_annex.md
• ./doc/api/dora4_group_analytics.md
• [-] ./doc/development/documentation/site_architecture/release_process.md (no entry - redirects to external link)
• ./doc/development/what_requires_downtime.md
• [-] ./doc/gitlab-basics/create-your-ssh-keys.md (already listed)
• ./doc/integration/jira_development_panel.md
• ./doc/security/cicd_variables.md
• ./doc/topics/git/lfs/migrate_from_git_annex_to_git_lfs.md
• ./doc/university/training/topics/agile_git.md
• ./doc/user/abuse_reports.md
• ./doc/user/admin_area/abuse_reports.md
• ./doc/user/project/integrations/jira.md
• ./doc/user/project/integrations/jira_integrations.md
• ./doc/user/project/merge_requests/merge_request_approvals.md