Add pre-processing script to enable all our code generation tools to work with $refs

The root problem is that our TS-type-generation tool,
jsonschema-to-typescript, expects $ref paths to be relative to the
schema root directory, while our Python-type-generation tool,
datamodel-codegen, expects $ref paths to be relative to the file
containing the $ref.

To work around this, I'm adding a pre-processing step to the Python type
generation code which converts the paths to look like datamodel-codegen
expects.

Author: mfisher87

packages/schema/src/schema/project/layers/symbology/vectorColor.json

@@ -10,7 +10,6 @@
         },
         "selectedAttribute": {
             "type": "string",
-            "title": "Attribute",
             "description": "The selected attribute for varying the color"
         },
         "colorRamp": {

packages/schema/src/schema/project/layers/vectorLayer.json

@@ -19,7 +19,16 @@
     },
     "symbology": {
       "type": "object",
-      "description": "The user inputs for symbology options"
+      "description": "The user inputs for symbology options",
+      "additionalProperties": false,
+      "properties": {
+        "color": {
+          "$ref": "project/layers/symbology/vectorColor.json"
+        },
+        "size": {
+          "$ref": "project/layers/symbology/vectorSize.json"
+        }
+      }
     }
   }
 }