[next] add global slot for layout

[userquin]

Is your feature request related to a problem? Please describe.

I need to add a prompt dialog and there is no way to add it only once.

I need to add the component to some home slot and also to a content slot.

Since the prompt is shown using position fixed I need to use also Teleport to move the component to the body.

Describe the solution you'd like

Instead adding the component twice just provide a layout slot to be included under the layout element.

Describe alternatives you've considered

No response

Additional context

The use case is for example when using PWA with prompt for update.

You can check the PR on the vite plugin pwa repo for New theme, check the index module on docs/.vitepress/theme folder and the ReloadPrompt.vue on components folder.

Validations

• Follow our Code of Conduct
• Read the docs.
• Read the Contributing Guidelines.
• Check that there isn't already an issue that asks for the same feature to avoid creating a duplicate.

[kiaking]

Sounds good. Maybe we add slot named:

• layout-top
• layout-bottom

<!-- Layout.vue -->
<template>
  <div class="Layout">
    <slot name="layout-top" />

    ...

    <VPFooter />

    <slot name="layout-bottom" />
  </div>
</template>