Add support in ui-library for tree data structures

[asmecher]

For #10404, we'll need a UI tool that'll allow the construction of arbitrarily nested trees. For example, we might support a 4-level tree:

• Subject
  • Mathematics
    • Calculus
      • Integral Calculus
      • Differential Calculus
    • Geometry
      • Trigonometry
      • Non-Euclidean Geometry
    • Discrete Mathematics
      • Logic
      • Set Theory
  • Physics
    • ...
  • Biology
    • ...
• Funder
  • Agency A
  • Agency B
  • Agency C
• Thematic Area
  • Adaptation to Climate Change
  • Environmental Sustainability

At the simplest, we could just require a tool that supports the presentation of the tree, and leave editing (and rearrangement and deletion confirmation) to modals.

We may need fine-grained server-side control over how the tree can be re-arranged -- for example, control over "Mathematics" and its contents could belong to User A, and "Geometry" to User B, so while it's tempting to permit drag-and-drop rearrangement, that might complicate things unnecessarily. Rearranging the tree should be an uncommon task.

[Devika008]

Here's a quick prototype of how the tested tables can work

Screen.Recording.2024-09-19.at.17.16.00.mov

Prototype can be found here: https://www.figma.com/proto/Wf7sDlUg2372jaKKTJ0Mgz/OJS-3.4-3.5?page-id=7200%3A7069&node-id=8927-11021&node-type=frame&viewport=1746%2C-16265%2C0.2&t=xtFViZnaW9GHQRLs-1&scaling=min-zoom&content-scaling=fixed&starting-point-node-id=7200%3A7075

1. We already have similar functionality in our new navigation, so implementing this should be straightforward. It will work like the PrimeVue panel menu component found here: https://primevue.org/panelmenu/
2. The "Add Category" option will only allow the addition of main categories, removing the form field for the parent component.
3. To add subcategories, you can click "More Options" and add child items below the main categories. The table will keep expanding with nested categories unless a limit is set.
4. Also I think we should only allow ordering of main categories i.e. the first level and nothing below that
5. If an editor/section editor is assigned to a category no matter the level we display them in the table