Improve the sidenav navigation

[bkjohnson]

Issue Description

The static content has a left sidenav component that doesn't seem consistent. Sometimes the user will see a sidenav like this:

(from Palo Alto's Medical records office page)

On other pages the user may see a sidenav like this, where an accordion is present where only one item can be opened at a time:

(from the eligibility page for burials & memorials)

I think it would be good if the sidenav structure & behavior was consistent across all pages.

Acceptance Criteria

• [ ] Decide on a single sidenav presentation style & structure

[k80bowman]

Is this a design system issue or a static pages issue?

[bkjohnson]

:spaghetti: A bit of both, maybe? There's a static pages template that's using the SideBarMenu class from formation. Then there's also the facilities sidebar template which relies on some site-wide JS in vets-website.

I think there's an opportunity for a Design System sidebar/sidenav component in order to provide consistency.

[k80bowman]

Just to be clear, is your recommendation that we create a sidebar web component?

[bkjohnson]

Yes, unless there's some business or design reason why we have different sidebar components for different pages.

[k80bowman]

I know you brought up creating a sidebar web component the other day and I agree, I think it's a good idea. We already have the design, we could definitely prioritize building a web component.