Support any entity, not just nodes

Problem/Motivation

The new custom field only works on nodes, but nothing stops the module from working with other entity types, like paragraphs or custom entities.

Proposed resolution

The module assumes that the checklist will be shown in the node full-view mode page. Discard this assumption, and add the content type and id of the entity that has the checklist to the checklists HTML tag.

Affected components:

- JavaScript calls to toggle the topics
- Routing: remove the node parameter
- Controller: Load the entity from the request payload