fix: show a full page 404 when a project is not accessible

[leafty]

Details:

• Add a "Error 404 - Project no found" page with contents similar to v1 not found page.
• Refactor the project page v2 routing and components (see <Outlet> and useOutletContext())

Examples:

• https://renku-ci-ui-3162.dev.renku.ch/v2/projects/flora.thiebaut/no-project
• https://renku-ci-ui-3162.dev.renku.ch/v2/projects/1234

/deploy

[RenkuBot]

You can access the deployment of this PR at https://renku-ci-ui-3162.dev.renku.ch

[ciyer]

praise: This code improvements here are very nice, and the use of Outlet allows for a better structure to the project page!

I found a situation were the new 404 page should be shown, but the old error message is still displayed: https://renku-ci-ui-3162.dev.renku.ch/v2/projects/foo/test/sessions/01HZ79337RV3CCZCQSMW8F0V5F/start

[leafty]

praise: This code improvements here are very nice, and the use of Outlet allows for a better structure to the project page!

I found a situation were the new 404 page should be shown, but the old error message is still displayed: https://renku-ci-ui-3162.dev.renku.ch/v2/projects/foo/test/sessions/01HZ79337RV3CCZCQSMW8F0V5F/start

Fixed in 7e10153.

[ciyer]

Fix looks good!

[leafty]

@ciyer can you re-approve? There was a merge conflict and also the "Delete" button redirected to nowhere (fixed).

[ciyer]

LGTM!

[RenkuBot]

Tearing down the temporary RenkuLab deplyoment for this PR.