Replace cleanup fetch requests with app API route.

[OliverDudgeon]

The fetch requests made by the bootstrap test often fail (Unexpected end of JSON — a playwright issue — N.B. should find a GitHub issue for this). Instead a API route could be created in the app (disabled in production) that would cascade delete all projects -> products -> units -> organisations. This could be called as a "test" in Playwright via this pattern.

await page.route('**/*', route => {
  route.fulfill({
    status: 404,
    contentType: 'text/plain',
    body: 'Not Found!'
  });
});

[OliverDudgeon]

Tests seem more reliable at the moment. No this is low priority for now.