Move all existing project routes under /-/ scope

From https://gitlab.com/gitlab-org/gitlab-ce/issues/61985#note_172148991

Because both project and group have wildcard in their path.

Every time a Rails controller has to match an endpoint, it has to do this giant regex comparison. I've seen this show up in our performance traces, somewhere.

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For more information see #214217 (closed)

Project routes based on sidebar nav

• Project activity
• Repository - #118849 (closed)
• Issues - #118849 (closed)
• Merge Requests - #118849 (closed)
• CI/CD - #118849 (closed)
• Security & Compliance - !24287 (merged)
• Operations - !20456 (merged)
• Packages
• Wiki - !21185 (merged)
• Analytics
• Snippets - #223719 (closed)
• Project members - !26967 (merged)
• Settings - gitlab-foss!28435 (merged)
  • Webhooks - !57734 (merged)
  • Pages

Removing deprecated routes

Should be handled in separate issue => #28848 (closed)