Added the functionality to delete file segments if they exist

### Changes
- Modified the `CloudFilesProvider.DeleteObject` logic to check to see if the file is being deleted is a manifest file.  If so, then it retrieves all the files in the manifests and deletes them as well.
- Fixed a bug in the `CloudFilesProvider` that caused the token to be re-fetched each time a web request was made to the service.
- Removed unused constants from the `CloudFilesProvider` class