Lessons and other initial edits

[lucytallents]

No description provided.

[csev]

@lucytallents - Why did you retract this - your changes to add the mod folder are spot on. The lessons.json changes look like they are going in a kind of good direction.

[lucytallents]

@csev I retracted because only some changes were supposed to go to your tsugiproject/koseu-site repo - the others were specific to verdantlearn's koseu repo and won't be helpful to other koseu adopters. I'm working on Koseu again now so will see if I can sift through and push only the relevant changes, but it may not happen this month, depending on how my prep progresses for a course that goes live this Monday 21st!