feat: Update logic graph styling

[ianjon3s]

What does this PR do?

Visual changes to the logic graph, summarised as:

• Increased contrast to nodes, branches and add-node links
• Standardised padding across hangers and branches to increase visibility of structure
• Updated styling of portal nodes to show clear demarcation between node link (enter portal) and menu link (configure portal)
• Only questions and checklists without answers present in sticky-note styling
• Section nodes have dashed border to add subtle visual organisation to graph
• Assigned flag colours no longer apply to full background of an option - reduces contrast issue (made more acute by small size)
• GOV.UK focus style on nodes and add-node links
• Clearer green outline to mark traversed nodes

Preview

Before:

After:

[github-actions]

Removed vultr server and associated DNS entries

[DafyddLlyr]

@ianjon3s Destroyed and recreated the Vultr instance here this morning as I noticed it was failing.

Let us know when this is ready for review as I know you're keen to move it forward 👍

[ianjon3s]

Restyling the graph in the Editor

[ianjon3s]

Thanks @DafyddLlyr ! I've marked this as ready-to-review as I believe it is in good shape from a code perspective.

[DafyddLlyr]

A nice refactor in future would be to replace this with styled components to match the rest of the codebase. Not a small task and no rush really, but it would be nice from a consistency point of view.

[ianjon3s]

Agreed, I'll see about doing this as a longer-term piece of work.

[DafyddLlyr]

Ha! I forgot about this neat little trick.

I think this means we need to update the "how to add a component" guide to say we need to add a style for a new component also (not sure how this would handle defaults / new components right now).

[ianjon3s]

In this case the style is only being used/applied as an enhancement for type-Section, so we wouldn't need a style unless it needed to be distinctive from the other components. As long as the type is set on a new component it'll pull through and be used if necessary (if I understand your point correctly).

[DafyddLlyr]

Looking great!