Prism capabilities: Allow 'facets' property

E.g. there are 3-facet and 8-facet prisms. Storing the facet count in a machine readable property could allow lighting programs to better visualize prisms.

QLC+ just added this functionality in a similar way using the Res1 attribute for PrismEffectOn capabilities (see mcallegari/qlcplus@a2d94c4f9a87594ccfaf227ef8faf06e698d4f41 and mcallegari/qlcplus@02aea5ffe34e99fbc51abd09dc8fdc2bf3da54ef), so we could use that data there.

Example:

  "Prism": {
    "capabilities": [
      {
        "dmxRange": [0, 10],
        "type": "NoFunction"
      },
      {
        "dmxRange": [11, 20],
        "type": "Prism",
-       "comment": "3-facet"
+       "facets": 3
      },
      {
        "dmxRange": [21, 30],
        "type": "Prism",
-       "comment": "8-facet"
+       "facets": 8
      }
    ]
  }

The capability name should be 3-facet prism instead of Prism (3-facet) then.

See the docs on how to add new type-dependent properties.

Start with docs/capability-types.md, especially the section on type-dependent properties, then inspect existing Prism capability definitions. Add a machine-readable facets property for Prism capabilities and update the capability names to use the proposed 3-facet prism form instead of Prism (3-facet).