Allow specifying extra volumes

[marrrcin]

Description

• add ability to specify additional volumes, especially memory-backed emptyDir to address

Bus error. It is possible that dataloader's workers are out of shared memory. Please try to raise your shared memory limit.

while running PyTorch with multiple GPUs/workers using kedro-kubeflow.

• refactor configuration to Pydantic, with some simplifications related to defaults ( ⚠️ this PR changes the behaviour of resources requests/limits - they will be always set to defaults in the compiled pipeline, but it's not breaking IMHO).

PR Checklist

• Tests added
• Changelog updated

[szczeles]

Fantastic work!!!!