Add static apply method to enable creating RequestConfig from Scala

[sbrunk]

With the factory, it should be possible to create RequestConfig instances from Scala and Java.

This seems necessary because User is an inline value class. See #275

I'm not sure if it also makes sense to add a String getter for user.

[raulraja]

Thank you @sbrunk !
I took the liberty to merge main back into your branch and apply spotless so the build would pass.

I'm guessing there are more places like this one since we have not yet done a pass to make all the classes and functions compatible for all JVM langs but Kotlin. The same applies to suspend functions which we also plan to address in a better way than what we are doing now wrapping them.

[raulraja]

this change will be available since 0.0.3-alpha.2

[sbrunk]

Thanks @raulraja! I'll continue playing with it :)