[v1 DOCS] Add banner with link to the new docs

[nataliaElv]

Let's add a banner to the Argilla v1 docs to point towards Argilla v2 docs while these two coexist.

[nataliaElv]

@davidberenstein1957 Could you share the example you mentioned? If it still exists...

[burtenshaw]

Here is an example of Haystack's current view on v1 docs:

Before this, they had a fixed banner add to the HTML template.

[burtenshaw]

@davidberenstein1957 posted this haystack image that shows the three core parts warning, welcome, and migraiton

[Amelie-V]

Maybe simply changing the walkthrough video for a serie of callout similar to the Haystack example. The red warning (first screenshot is similar to the one we had in the 1.29 highlights.

Looking at these cool callouts, I'm not sure we have to created a top fixed banner to the docs pages.

[davidberenstein1957]

NEW DOCS

[davidberenstein1957]

OLD DOCS

[nataliaElv]

Looking nice!