[FEAT] Introduce various plugins to split the bpmn-visualization API provided by BpmnElementsRegistry

[tbouffard]

Rationale

Currently, we can do this by using the bpmn-visualization API provided by BpmnElementsRegistry.
Having such plugins would

• test the plugin infrastructure in real life and detect issues and/or new needs
• prepare the split of BpmnElementsRegistry. See also [REFACTOR] Split the code of BpmnElementsRegistry and the code of its collaborators bpmn-visualization-js#2803

Proposal

methods: all related methods from BpmnElementsRegistry (try if we can use the Pick utility type to get the right signature)

use case	class	id
CSS classes management	CssClassesPlugin	css
overlays management	OverlaysPlugin	overlays
search elements	ElementsPlugin	elements
style elements	StylePlugin	style

Notice that

• OverlaysPlugin already exists and some code could be shared with [FEAT] Introduce a plugin to expose the bpmn-visualization "overlays API" with names as parameters #74 (setVisible method).
• ElementsPlugin is going to expose some common methods with [FEAT] Introduce a plugin to expose the bpmn-visualization "elements API" with names as parameters #76 (search by kind), so some code could probably shared. Be also aware of the upcoming [FEAT] Add new methods to only retrieve the BPMN semantic of elements in the model bpmn-visualization-js#2813

See also the plugins providing methods by name for consistency:

• [FEAT] Introduce a plugin to expose the bpmn-visualization "CSS classes API" with names as parameters #73
• [FEAT] Introduce a plugin to expose the bpmn-visualization "overlays API" with names as parameters #74
• [FEAT] Introduce a plugin to expose the bpmn-visualization "style API" with names as parameters #75
• [FEAT] Introduce a plugin to expose the bpmn-visualization "elements API" with names as parameters #76

Tasks

Beta Give feedback

1. CSS. feat: introduce CssClassesPlugin #288
2. Overlays. Also update the existing demo to only use the plugin and not the BpmnElementsRegistry implementation. feat: expose bpmn-visualization methods in OverlaysPlugin #123
3. Search elements feat: introduce ElementsPlugin #139
4. Style elements. Also update the existing demo to only use the plugin and not the BpmnElementsRegistry implementation. feat: introduce the StylePlugin #286