docker-native goal: Support custom startup parameters in AWS bootstrap.sh

[DerChris173]

Hi Micronaut team!

First, thank you for writing such a cool piece of software and making producing GraalVM native binaries sweet and easy!

I would like to propose a small feature:
Allow customizing the startup parameters of the AWS native application inside the generated bootstrap.sh.

For my concrete use case, I would like to override the standard netty settings using -Dio.netty.* startup flags. I don't think the default ones are optimal for the AWS lambda use case (maybe checking for best default values could be a separate issue to check?).

E.g. I would like to have the option to have this kind of bootstrap:

./func -Djava.library.path=/function -Dio.netty.noPreferDirect=true -Dio.netty.allocator.numDirectArenas=0 -Dio.netty.noUnsafe=true

If you would accept this request and I can support in this work, I think I could add this feature myself even based on existing arguments for GRAALVM_ARGS

Thank you for your time!