update: rewriting coroutines basics for coroutines guide updates (#4474)

* update: rewriting coroutines basics for coroutines guide updates

* update: implementing comments from first review round

* update: adding information on extracting coroutine builders from scope

* fix: fix indentation in new code example

* implementing comments from Dmitry

* implementing second round of reviews from Seb

* making code snippet runnable

* removing runnable example

* implementing additional review comments about coroutine basics

* fix: code comments in the first example after introducing delay()

* making this expression explicit in all examples for launch and async

* part2 adding CoroutineScope

* implementing comments from Natasha

* update: refining sentence about coroutine context

* update: reworking the comparison of withContext and coroutineScope

* small update about coroutineScope

* implementing last round of review comments from Natasha

* fix: adding commas to new sentence about extracting launch()

* fix: colon to period

* update: implementing comments from Dima

* fix: refactoring example

* implementing TWr review comments

* implementing additional comments from TWr review

Author: daniCsorbaJB