feat: add vp-raw container

[brc-dd]

fixes #591, fixes #199

Trying to support this syntax:

::: raw
No styles and router interception here.
See the related issues for use-cases.
Required mainly when documenting components.
:::

Alternatively:

<div class="vp-raw">
Above `::: raw` syntax is equivalent to this.
Will work on any element, not-necessarily `div`,
just looking for the `vp-raw` class here.
<div>

Class can be added directly to components too:

<Foo class="vp-raw" other="props" />

(if the component can handle that, i.e. adds class
to root element -- no inheritAttrs stuff is there.)

TODO:

• Either document this (#199 (comment)) or provide an option to enable style isolation.
• Update docs.