Add option for making calendar / timeline weeks go Monday - Sunday instead of Sunday - Saturday

[ragesoss]

We get periodic requests from instructors to have the dates work on a Monday through Sunday basis. I suspect that this would not be a welcome change for some people if done universally, so we'd probably need to add it as an option that can be switched back and forth for an individual course. It probably involves a lot of tweaks to the frontend date code, and a bit on the backend as well.

[PR4NJ41]

@ragesoss Can i work on this issue ?

[ragesoss]

Sure. This will likely need some very thorough tests.

[PR4NJ41]

@ragesoss I have modified Calendar according to the issue. Can you tell what needs to be done in Timeline. I can find that the Timeline Dates in heading are needed to be changed. Is there more to it ? Thanks