Fix relationship between node service and mounter interface

[torredil]

What is this PR about? / Why do we need it?

This patch is 2/2, designed to improve the architecture of the code base with the goal of promoting a more cohesive and understandable design that makes it easier to reason about the driver and make future modifications or extensions more intuitive.

More specifically, this PR fixes the relationship between the node service and mounter interface, allowing for a platform agnostic node service.

Summary of Changes

• Integrate resizeFs functionality into mounter package
  • Updated the NodeStageVolume and NodeExpandVolume RPCs to use the Resize method directly from the Mounter interface, instead of creating a new ResizeFs instance.
• Remove DeviceIdentifier interface
  • Replaced the usage of deviceIdentifier with direct calls to os.Lstat and filepath.EvalSymlinks.
• Refactor node service to be platform agnostic
  • Moved platform-specific code from node_linux.go and node_windows.go to mount_linux.go and mount_windows.go.
• Refactor node service initialization and dependency injection
  • Improved modularity and testability by injecting dependencies (metadata.MetadataService, Mounter, metadata.KubernetesAPIClient) into the NewDriver() and NewNodeService() functions.

What testing is done?

• manual
• make test && make verify
• CI

[github-actions]

Code Coverage Diff

File	Old Coverage	New Coverage	Delta
github.com/kubernetes-sigs/aws-ebs-csi-driver/pkg/driver/node.go	80.6%	92.0%	11.4
github.com/kubernetes-sigs/aws-ebs-csi-driver/pkg/mounter/mount.go	Does not exist	75.0%
github.com/kubernetes-sigs/aws-ebs-csi-driver/pkg/mounter/mount_linux.go	Does not exist	45.7%
github.com/kubernetes-sigs/aws-ebs-csi-driver/pkg/mounter/safe_mounter.go	Does not exist	100.0%

[AndrewSirenko]

Few initial questions/comments, will review once more when unit tests are ready. Thanks for this!

[torredil]

/retest

[torredil]

/retest

[ConnorJC3]

/lgtm

[torredil]

/approve

Thank you very much for all of the great effort in reviewing all the changes made across the refactoring PRs @ConnorJC3 @AndrewSirenko

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

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