[Tutorial] Turn Loops and Recursion into Recursion only

[cuihtlauac]

• Move imperative & mutability related content to dedicated content
• Make it a recursion centered tutorial
• Properly introduce mutually recursive types and functions
• Tail recursion and tail recursion modulo
• Higher-Order iterators: map, fold, unfold, bind, app
• Non structural recursion (Ackermann or Syracuse)
• Infinite loops as recursion w/o memory leaks
• Recursion on sequences
• Standalone, short and executable examples

[Dev-JoyA]

@SaySayo i would love to work on this task

[SaySayo]

You can go ahead. Let me know if you need any clarification.