add/migrate exercises on type classes to use given values and extension methods week 11

[bjornregnell]

related to #564

[bjornregnell]

almost done no by recent commits up to https://github.com/lunduniversity/introprog/commit/1d3c3897c05fca6f971426e9fdac16c35e96d1c7

this is whats left:

• [x] read the advanced exercises in w11 and think hard on what this should be about
• [x] delete exercises that are outdated
• [x] migrate or develop new exercises to teach type classes by utilizing convenient Scala 3 stuff and updating them from impiicits to given
• [x] double-check solutions
• [x] update the initial goal section of the context exercise