Code demo or new component of an info side-panel for app guidance

[droumis]

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

Complex apps require guidance for new users, but permanent instructions in the main sidebar (where app widgets/controls usually live) can be distracting.

Describe the solution you'd like

A toggleable slide-based (e.g. with Previous, Next buttons) side panel.

Describe alternatives you've considered

Instructions on the main plot or main sidebar.

Additional context

For instance, GCP's Learn Tutorial sidebar:

[MarcSkovMadsen]

An alternative is a Button openening a Modal with Docs. Or a link to external Docs.

[ahuang11]

The current templates support programmatic opening/closing of a sidebar. However, they're only on the left side; would be nice to have it on the right too.

Alternatively, ideally, we completely refactor jinja2 templates into Panel components, then maximum flexibility achieved :D

Relevant #7250