Migrate to 1.0

[sifferhans]

• Implement new layouts system sveltejs/kit#6174
• Prerendering overhaul sveltejs/kit#6392
• [breaking] ssr/hydrate/router/prerender.default are now configurable in +page(.server).js and +layout(.server).js sveltejs/kit#6197
• feature: Replace sveltekit:* with valid HTML attributes like data-sveltekit-* sveltejs/kit#6170
• Form actions sveltejs/kit#6469
• rename prerendering to building, remove config.kit.prerender.enabled sveltejs/kit#7762
• Replace data-sveltekit-prefetch/prefetch(...)/prefetchRoutes(...) sveltejs/kit#7776
• Upgrade to Vite 4 sveltejs/kit#7543
• [breaking] rename invalid(...) and ValidationError sveltejs/kit#8012