Screenshot

[drag & drop image(s) here!]

Description

New users going through https://superset.apache.org/docs/intro have to open the overview video for visual introduction in a new page. We should embed the video into the documentation for better impression.
[describe the issue here!]

Design input

[describe any input/collaboration you'd like from designers, and
tag accordingly. For design review, add the
label design:review. If this includes a design proposal,
include the label design:suggest]