Combine plugin and pod paths into one KubeletPath

[mauriciopoppe]

What type of PR is this?

Uncomment only one /kind <> line, hit enter to put that in a new line, and remove leading whitespaces from that line:

/kind api-change

/kind bug
/kind cleanup
/kind design
/kind documentation
/kind failing-test
/kind feature
/kind flake

What this PR does / why we need it:

Replaces the command line arguments kubelet-pod-path and kubelet-csi-plugins-path with kubelet-path, also removes the PathContext enum from the FS v1beta3 protobuf and the internal server implementation

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Continues on the work that @jingxu97 did on #149

Does this PR introduce a user-facing change?:

`--kubelet-pod-path` and `--kubelet-csi-plugins-path` replaced with `--kubelet-path`, `PathContext` removed from the Filesystem v1beta3 API

/cc @jingxu97 @ddebroy

[mauriciopoppe]

Results of the tests of 6c1d470

go test -v .\integrationtests\ -run TestFilesystemAPIGroup
=== RUN   TestFilesystemAPIGroup
=== RUN   TestFilesystemAPIGroup/v1beta2FilesystemTests
=== RUN   TestFilesystemAPIGroup/v1beta2FilesystemTests/PathExists_positive
=== RUN   TestFilesystemAPIGroup/v1beta2FilesystemTests/IsMount
=== RUN   TestFilesystemAPIGroup/v1beta1FilesystemTests
=== RUN   TestFilesystemAPIGroup/v1beta1FilesystemTests/PathExists_positive
=== RUN   TestFilesystemAPIGroup/v1beta1FilesystemTests/IsMount
=== RUN   TestFilesystemAPIGroup/v1alpha1FilesystemTests
=== RUN   TestFilesystemAPIGroup/v1alpha1FilesystemTests/PathExists_positive
=== RUN   TestFilesystemAPIGroup/v1alpha1FilesystemTests/IsMount
--- PASS: TestFilesystemAPIGroup (0.37s)
    --- PASS: TestFilesystemAPIGroup/v1beta2FilesystemTests (0.12s)
        --- PASS: TestFilesystemAPIGroup/v1beta2FilesystemTests/PathExists_positive (0.07s)
        --- PASS: TestFilesystemAPIGroup/v1beta2FilesystemTests/IsMount (0.06s)
    --- PASS: TestFilesystemAPIGroup/v1beta1FilesystemTests (0.12s)
        --- PASS: TestFilesystemAPIGroup/v1beta1FilesystemTests/PathExists_positive (0.07s)
        --- PASS: TestFilesystemAPIGroup/v1beta1FilesystemTests/IsMount (0.06s)
    --- PASS: TestFilesystemAPIGroup/v1alpha1FilesystemTests (0.12s)
        --- PASS: TestFilesystemAPIGroup/v1alpha1FilesystemTests/PathExists_positive (0.08s)
        --- PASS: TestFilesystemAPIGroup/v1alpha1FilesystemTests/IsMount (0.05s)
PASS
ok      github.com/kubernetes-csi/csi-proxy/integrationtests    0.707s

[ddebroy]

Thanks @mauriciopoppe. LGTM mod one comment about field numbers. (reposted below)

[ddebroy]

Thanks @mauriciopoppe. LGTM mod one comment about field numbers.

[ddebroy]

Somehow the comment here got deleted. Can we use reserved https://developers.google.com/protocol-buffers/docs/proto3#reserved here to prevent the re-numbering?

[mauriciopoppe]

I think this is useful if the same proto file is used across versions, because we have new protos for every version I'm not sure if this makes sense in this project

[ddebroy]

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ddebroy, mauriciopoppe

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