Move files_handler_params default from FileContentsManager to ContentsManager#1496

MaicoTimmerman wants to merge 1 commit intojupyter-server:mainjupyter-server/jupyter_server:mainfrom

MaicoTimmerman:move-files_handler_params-to-contentMaicoTimmerman/jupyter_server:move-files_handler_params-to-contentCopy head branch name to clipboard