LET: a Tutor plugin to simplify Open edX customization

By the way, I think there’s a lot of overlap here with OEP-68: Openfeature Toggles - once the changes proposed in that OEP are accepted, I think it would be much simpler and easier to implement this sort of plugin, since there’d be a unified API for all the config settings built in. Please comment on that PR if you have thoughts.