Feature/timeline

[con322]

Proposed Changes

• New timeline block, allows user to add milestones with inputs for heading (above the timeline line), title and content.

Resolves #128

[jaymcp]

This works really nicely; great work!
One thing, though, is that the front-end breaks if JavaScript is disabled/not available. I'd suggest adjusting the layout in CSS with a sensible fallback if the .no-js class is present.

[con322]

If there's no js the timeline milestones will be stacked so that they are all visible at once due to scroll functionality being disabled when js is disabled.

[jaymcp]

LGTM!