[Kotlin] Fix Spring Kotlin generation of array/map models

[cbornet]

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• Fix generation of nested map/arrays and map/array models (code taken from AbstractJavaCodegen)
• Fix data class extension constructor (there's still an issue when parent has attributes and mutableModels is false that will need to be fixed in another PR)
• Fix generation of @Generated annotation

@jimschubert (2017/09) heart, @dr4ke616 (2018/08) @karismann (2019/03) @Zomzog (2019/04) @andrewemery (2019/10) @4brunu (2019/11) @yutaka0m (2020/03)

[wing328]

Tested locally with nested map/arrays and map/array models and the code compiles without issues.