provider/azurerm: Addition of documentation for the new Storage Blob upload options

Author: stack72

website/source/docs/providers/azurerm/r/storage_blob.html.markdown

@@ -60,7 +60,13 @@ The following arguments are supported:
 
 * `type` - (Required) The type of the storage blob to be created. One of either `block` or `page`.
 
-* `size` - (Optional) Used only for `page` blobs to specify the size in bytes of the blob to be created. Must be a multiple of 512. Defaults to 0. 
+* `size` - (Optional) Used only for `page` blobs to specify the size in bytes of the blob to be created. Must be a multiple of 512. Defaults to 0.
+ 
+* `source` - (Optional) An absolute path to a file on the local system
+
+* `parallelism` - (Optional) The number of workers per CPU core to run for concurrent uploads. Defaults to `8`.
+
+* `attempts` - (Optional) The number of attempts to make per page or block when uploading. Defaults to `1`.
 
 ## Attributes Reference