feat(boids): add boids and particle life demo

Add linkLabel to AlgorithmEntry. The info panel shows it instead of
"Wikipedia" when set, for links that are not Wikipedia.
Tick the boids item in ROADMAP.md and add a Boids 3D item.

src/app/constants/UrlConstants.ts

@@ -21,6 +21,8 @@
   static readonly DOUBLE_PENDULUM_WIKI = 'https://de.wikipedia.org/wiki/Doppelpendel'
   static readonly CLOTH_SIMULATION_WIKI = 'https://en.wikipedia.org/wiki/Cloth_modeling'
   static readonly XPBD_WIKI = 'https://www.emergentmind.com/topics/extended-position-based-dynamics-xpbd'
+  static readonly BOIDS_WIKI = 'https://de.wikipedia.org/wiki/Boids'
+  static readonly PARTICLE_LIFE_WIKI = 'https://particle-life.com'
   static readonly GPU_COMPUTING_WIKI = 'https://en.wikipedia.org/wiki/General-purpose_computing_on_graphics_processing_units'
   static readonly DATA_STRUCTURE_WIKI = 'https://de.wikipedia.org/wiki/Datenstruktur'
   static readonly FOUR_COLOR_THEOREM = 'https://de.wikipedia.org/wiki/Vier-Farben-Satz'