* Update webpack-config to more closely align with SilverStripe core modules
* Automated linting
* Remove all JS linting errors, use let/const for assignment, do not reassign callback arguments
* Rebuild dist files, remove yarn lock from build command, remove source map files
All bulk handlers and the bulk uploader now use a common HTTPBulkToolsResponse to return a common json format and handle errors. The front end uses this json to update the drifield accordingling.
