Support was recently added to edx-platform to add customisised default grade
designations, this change adds support for them to this MFE as well to bring it
to partiy with the edx-platform UI
It also refactors the grading-settings page to use React Query and updates the
logic used when partitioning grades by default to make it work better when there
are more than 5 partitions.
Co-authored-by: Farhaan Bukhsh <farhaan@opencraft.com>
