Use google api batch request to update blob

Blob updates is done asynchronously by workers processing documents. Workers are scheduled to deal with org.nuxeo.ecm.liveconnect.update.BatchUpdateBlobProvider.MAX_RESULT documents. As many workers as needed are scheduled to refresh all the documents.

Currently a request to the google drive api is issued for each document to be updated which can be significantly improved.

We can use batch request instead.