Create a static sidebar for comparator view

[HonkingGoose]

What feature would you like to have?

We don't yet have any sidebar for our comparator view.

The basic idea is that the sidebar grabs all the change-log headings and shows them in a list. For now the list items can just be simple li tags which display the changelog heading, no anchor tags/URLs.

I'd say something like this is enough to get started with:

• [ ] Backend code to grab changelog headings and put them into a item on the sidebar
• [ ] Sidebar component as close as possible to the Figma design
• [ ] No hover states, active states
• [ ] List items are just plain text with no functionality to them

What problem will this feature solve?

We need to have any sidebar at all before we can work on #157. To make the items in the sidebar function as links we need issue #125 to be done.

Even a "dumb" sidebar can provide a bit of value as a table of contents.

Do you want to help make the feature?

Yes

Is there anything else we need to know?

No response