[🐞] follow up on Vite's assetsDir support

[IgorMinar]

Which component is affected?

Qwik Rollup / Vite plugin

Describe the bug

This is a follow up on https://github.com/QwikDev/qwik/issues/6509

The remaining issues discovered when testing with:

"@builder.io/qwik": "https://pkg.pr.new/@builder.io/qwik@604e1ae",
"@builder.io/qwik-city": "https://pkg.pr.new/@builder.io/qwik-city@604e1ae",

• [ ] source files in public/ should be moved to dist/ as is, without honoring assetsDir (per Vite docs, assetsDir should be applied only to generated files accessible by browser clients)
• [ ] dist/_routes.json contains unprefixed paths (note that the _route.json file itself should not be prefixed even though it's generated because it's not a file that should be accessible by browser client)
• [ ] server/@qwik-city-static-paths.js contains suspicious code: p.startsWith("/build/") and p.startsWith("/assets/") which seem to ignore the assetsDir setting
• [ ] q-manifest.json contains "data-src": "/build/q-8xADQF12.css", which is likely wrong as it should be prefixed

Reproduction

see https://github.com/QwikDev/qwik/issues/6509

Steps to reproduce

No response

System Info

see https://github.com/QwikDev/qwik/issues/6509

Additional Information

No response

[gioboa]

• [x] source files in public/ should be moved to dist/ as is, without honoring assetsDir (per Vite docs, assetsDir should be applied only to generated files accessible by browser clients)
• [x] dist/_routes.json contains unprefixed paths (note that the _route.json file itself should not be prefixed even though it's generated because it's not a file that should be accessible by browser client)
• [x] server/@qwik-city-static-paths.js contains suspicious code: p.startsWith("/build/") and p.startsWith("/assets/") which seem to ignore the assetsDir setting
• [x] server/@qwik-city-not-found-paths.js ignores the assetsDir setting
• [x] q-manifest.json contains "data-src": "/build/q-8xADQF12.css", which is likely wrong as it should be prefixed