First pass at updating docs for the new external grading config
First pass at updating docs for the new external grading config

mwest1066/PrairieLearn,rbessick5/PrairieLearn,rbessick5/PrairieLearn,parasgithub/PrairieLearn,parasgithub/PrairieLearn,jakebailey/PrairieLearn,parasgithub/PrairieLearn,rbessick5/PrairieLearn,mwest1066/PrairieLearn,jakebailey/PrairieLearn,mwest1066/PrairieLearn,mwest1066/PrairieLearn,tbretl/PrairieLearn,parasgithub/PrairieLearn,jakebailey/PrairieLearn,jakebailey/PrairieLearn,rbessick5/PrairieLearn,tbretl/PrairieLearn,mwest1066/PrairieLearn,tbretl/PrairieLearn,tbretl/PrairieLearn,parasgithub/PrairieLearn,tbretl/PrairieLearn,rbessick5/PrairieLearn