updated content to reflect planning meeting prior to March 10. one activity and homework need to be updated.

Also added links to the class discussion and canvas to explain where
shared slide deck will be posted.

This reverts commit 43c28d25.

This reverts commit b7143f91.

This reverts commit 236a5d27.

This reverts commit fa2f8a37.

Copied from website-old
Needs to be merged with the things Jen was doing

textbook
other similar courses

Website is now forked from the master teaching website I'm using in
all my courses, and up to date with the latest version of the
CSE340 website

https://gitlab.cs.washington.edu/cse340/website/-/merge_requests/49/diffs