Add schema validation for collection files #369

This commit improves collection file editing and error detection
directly in the IDE. It adds YAML schema, IDE configuration and
automatic tests to validate it.

- Introduce a YAML schema for collection file.
- Use `yaml-language-server` for enhanced YAML support in VSCode.
- Add telemetry disabling in `configure_vscode.py` to respect user
  privacy.
- Add automated checks to validate YAML file structure against the
  schema.
- Remove unused properties and do not allow them in compiler.

.gitignore

@@ -14,3 +14,7 @@ node_modules
 
 # macOS
 .DS_Store
+
+# Python
+__pycache__
+.venv