Missing config options for chunk size and temporary path

Problem/Motivation

i'd like to increase the chunk size for faster uploads and specify temporary folder to be on the same volume as the final destination.
there are references in code for setting those values, but the config options are missing and not in settings form.
not sure but probably they haven't been ported to D8+ version yet.

Proposed resolution

adding the missing config options to the settings form and using the current default values as default values.

Data model changes

only config needs to be updated.
Add chunk_size and temporary_path to file_resup.settings

either keep default settings ?? config settings, or provide update hook for config update.