Rework kotlin generator with kotlin-poet

[sokomishalov]

PR goal is to decrease plain string manipulations to build kotlin API code and provide more safety while generating code.

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[mp911de]

Thanks for submitting a pull request. The generated code looks very different from the one that we had. We can only merge this if the resulting code is going to be the same (or have very minor differences). 5000loc of unrelated changes is an overkill currently.

[sokomishalov]

@mp911de Agree, but the resulting API code is exactly the same unless it wouldn't compile coz it generates only interface layer and implementation layer has not been changed. But still, I've tried to fit kotlinpoet to the previous view and provided these PRs (1,2) that received negative feedback, unfortunately. Anyway, I'll try to figure out something what we can do here.

[mp911de]

Thanks for the context. Given that Kotlinpoet doesn't seem to want to improve their dev experience and is rather limiting, I start to dislike the entire move into Kotlinpoet.

[sokomishalov]

JFYI fixed indentation, total diff decreased significantly and now is quite more readable Still trying to find some workarounds with current kotlin-poet API

UPD: appended license header as kdoc manually to the header

[sokomishalov]

Let's keep our generator as is for now