[Draft][test] : add sample chainsaw test for gpu-operator install

[rahulait]

This PR introduces a new end-to-end testing framework using Kyverno Chainsaw to validate GPU Operator installations and running tests. Chainsaw takes care of installing and uninstalling the resources and provides a declarative way to define tests. Initial test added in this PR provides comprehensive validation of the GPU Operator install and functionality.

Key changes added:

1. Development environment using devbox
   Added devbox.json file which contains the required tools to build and test the repository. Note: to use devbox, make sure you have devbox installed on the machine where the code is checked out.
2. Sample chainsaw test to install gpu-operator and run gpu pod
   Added one chainsaw test which can be run against any deployed k8s cluster with GPUs using:

root@machine:~ cd gpu-operator
root@machine:~ devbox shell
(devbox) root@machine:~ KUBECONFIG=<path to kubeconfig> chainsaw test e2etests/tests/

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[rahulait]

/ok to test ac86e8d