Composition API for bridge

[pi0]

Plan:

• Enable CAPI via imports [pooya]
• Compatibility for @nuxtjs/composition-api [daniel] (chore(deps): update all non-major dependencies #584)
• Add v3 app composables/util (feat!: use native vue-router composables #533) (defineNuxtPlugin, hooks, etc) [daniel]
• Auto import (chore(deps): update dependency nitropack to ^0.4.24 #481) [daniel]
• useMeta with vueuse/meta (chore(deps): update dependency untyped to ^1.2.0 #664) [daniel]
• script setup (chore(deps): update dependency get-port-please to v3 #678)
• Add v3 composables [pooya+daniel]

Checklist:

• Implement Nuxt3 Composition API for Nuxt 2 current mocked here
• Create virtual vue import to expose vue 3 composables from @vue/composition-api (?): feat(bridge): use useMeta in bridge projects framework#664
• Create virtual @nuxtjs/composition-api to make migration easier (?)
• Ensure @nuxtjs/composition-api is disabled to avoid usage conflict
• Support auto imoports (chore(deps): update dependency nitropack to ^0.4.24 #481)
• Support <script setup> (chore(deps): update dependency get-port-please to v3 #678)
• ...with top level await (context: feat(nuxt3): remove <script setup> transform and prefer top level await framework#579)

[pi0]

A quick comparison table between exports of vue@2, vue@3 and @vuejs/composition-api: https://docs.google.com/spreadsheets/d/1I1l4zr2GfyvDiDWj4QCSYCoMpa0ANzcvYWbiFT5MgWE/edit#gid=0

[pi0]

Checking unplugin-vue2-script-setup for <script setup> support for vue 2, it seems already a nice implementation but top-level await marked as unsupported. /cc @antfu Is it because of async setup() support for vue 2? We might find a way to suspend page navigations with fetch and asyncData() Without suspense supporting await for nuxt 2 seems a bad solution. We will keep with useLegacyFetch only that does not blocks navigation.

[pi0]

Most important composables are backported. We shall create a new issue for adding some more Nuxt 2 -only composables