Update canfar.md

[martinkilbinger]

Started md and cleanup of canfar doc

e and documentation style match the current standards

• Documentation has been added/updated consistently with the code
• All CI tests are passing
• API docs have been built and checked at least once (if relevant)
• All changed files have been checked and comments provided to the developer
• All of the reviewer's comments have been satisfactorily addressed by the developer