Kotlinx polymorphism with custom discriminator support

[some00]

• added new config with kotlinx, discriminator (/w custom name) and kotlinx_serialization
• remove discriminator properties from the generator in both base and derived classes
• set discriminatorValue in additionalProperties of derived classes
• add JsonClassDiscriminator the base classes in the template
• set SerialName to discriminatorValue in the template
• change base classes to sealed class from interface
• make variables in base classes abstract
• added test and new sample for validation

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[geirsagberg]

Great work, this is exactly what we are missing! Hopefully this can be merged somewhat quickly 👍

[wing328]

thanks for the pr

let's give it a try

[F43nd1r]

Isn't this spec incomplete? According to https://swagger.io/docs/specification/v3_0/data-models/inheritance-and-polymorphism/#discriminator, the discriminator property should be part of the listed properties.

I know this PR is already merged, but I'm hoping to get some clarification since we're looking forward to using this, but our spec does contain the discriminator property in the list of properties so I'm worried it won't work for us.

[some00]

@F43nd1r I don't know about the spec being incomplete. I'm no expert there.
I've modified the test resource, added the discriminator to the list of properties. The generator outputed the same exact code, so you should be able to use it with your spec.

[katepol]

@some00 thank you so much!!
the only thing, this condition is missing kotlin-multiplatform, || getLibrary().equals(MULTIPLATFORM)
could you please fix that?..:)

[katepol]

@wing328 should this functionality somehow be related to SchemaSupportFeature.Union?
To be honest, it very unclear what is SchemaSupportFeature.Union desined for, as there is no support anywhere

[yshrsmz]

I've created multiplatform port of this PR: #21772