* [VS Code] Add schemas for common files
- settings.json (paconn settings file)
- apiProperties.json
- apiDefinition.swagger.json
The schema for apiDefinition.swagger.json files is modified from the one found at http://schemastore.org/json/.
It includes many 'x-ms-' vendor extensions.
* [apiDefinition.swagger.schema.json] Copy from http://schemastore.org/json/