Clean up schema for table services

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Per https://gitlab.com/gitlab-com/infrastructure/issues/1709 (private to GitLab employees):

• Missing FK: project_id -> projects (20 entries violate this rule)
• Duplicate data: type could be an enum or 4-byte integer, save 17 MB
• Duplicate data: category could be an enum or 4-byte integer, save 14 MB
• Duplicate data: properties appears to be a structured field, would be more efficient broken out- accounts for 18 MB
• Index on boolean field: template
• Appears to be a large amount of dead data...