Redirect the project stats page to the static proxy => FEM

[goplayoutside3]

Linked Issue and/or Talk Post

Linked to zooniverse/static#442

Describe your changes

• Separate the list of project slugs into PRIVATE_PROJECT_SLUGS and OTHER_SLUGS so the list of private projects can be handled for the project /stats route.
• Redirect all project stats pages to the static proxy unless it is a known private project held back on PFE.
• All other project routes should be unaffected.

How to Review

• A known private project like aprajita/swdemo should display the PFE stats page: https://pr-7474.pfe-preview.zooniverse.org/projects/aprajita/swdemo/stats
• Any other project should get redirected to the FEM Project Stats page: https://pr-7474.pfe-preview.zooniverse.org/projects/zookeeper/galaxy-zoo/stats

Checklist

General UX

• Staging branch URL: https://pr-7474.pfe-preview.zooniverse.org/lab

Refactoring

• The PR creator has described the reason for refactoring
• The refactored component(s) continue to work as expected