Add JSON Schema for WordPress block.json files (#1879)

* start working on wordpress block.json schema

* add all top level definitions

* add deffinition of all subtypes

* fix patterns

* add refference links

* update example schema

* fix type of attribute.default

* remove __experimentalDuotone from the schema

* fix typo in references and switch to camelCase

* reorder properties to follow the pattern `type` `description` `default` `items` /  `properties`

* fix description length

* fix schema of `supports.spacing`

* update example

* cut down on length of descriptions

* remove unsupported `deprecated` attribute

src/api/json/catalog.json

@@ -453,6 +453,14 @@
       ],
       "url": "https://json.schemastore.org/bungee-plugin.json"
     },
+    {
+      "name": "block.json",
+      "description": "Schema WordPress block.json files",
+      "fileMatch": [
+          "block.json"
+      ],
+      "url": "https://json.schemastore.org/block.json"
+    },
     {
       "name": "CMake Presets",
       "description": "Schema for CMake Presets",