Use Kotlin metadata to retrieve parameter names of Endpoints

[snicoll]

Thanks to @sdeleuze I was able to improve the logic to extract parameters name of @ConfigurationProperties constructors with Kotlin. This results in a simpler setup for Kotlin users as they don't have to specify the java-parameters attribute on the compiler.

We're currently documenting that this is required but that's not strictly necessary so I wonder if we shouldn't apply the same trick there as well. We could then stop using the flag ourselves in our test suites to validate that this is working as expected (this would require some Kotlin-specific tests though).

[sdeleuze]

+1, java-parameters is not an attribute commonly used in Kotlin since this information is already available via Kotlin reflection.

[snicoll]

This is no longer applicable as DefaultParameterNameDiscoverer (which we uses) adds KotlinReflectionParameterNameDiscoverer automatically if Kotlin is detected.