[Kotlin] Implement new Concept Exercise: functions-basic

[dector]

This issue describes how to implement the functions-basic concept exercise for the Kotlin track.

Goal

The goal of this exercise is to show the student basic information about Kotlin functions.

Things to teach

• How to define a function.
• How to define default values for function arguments (show official Kotlin reference for this).
• How to return a value from a function.
• (Optionally) Single-expression functions.

Things not to teach

• Unit functions.
• Higher-order functions.
• Functions as a class members.
• Extension functions etc.

Concepts

• function-declaration.
• function-default-arguments.

Prerequisites

✔ None.

Resources to refer to

• (Kotlin Docs) Function declarations.
• (Kotlin Docs) Default arguments.

Representer

• TODO

Analyzer

• TODO

Implementing

• TODO

Help

If you have any questions while implementing the exercise, please post the questions as comments in this issue.