Cherry-pick #23335 to 7.11: Fix types for response fields of kubelet api

[ChrsMark]

Cherry-pick of PR #23335 to 7.11 branch. Original message:

What does this PR do?

This PR adjusts the types of the response fields from Kubelet stats/summary api so as to be consistent with the original types of the fields as defined on api's side: https://github.com/kubernetes/kubelet/blob/088ee84ea259bf9c445109ea75b2938dd39d2074/pkg/apis/stats/v1alpha1/types.go

Why is it important?

To avoid hitting integer overflow since we store as int64 while the api can serve values stored as uint64.
int64: -9223372036854775808 to 9223372036854775807
uint64: 0 to 18446744073709551615

Closes #19475

[elasticmachine]

Pinging @elastic/integrations (Team:Platforms)

[elasticmachine]

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• Build Cause: Pull request #23384 updated

• Start Time: 2021-01-07T08:36:19.871+0000

• Duration: 48 min 26 sec

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Test	Results
Failed	0
Passed	2287
Skipped	505
Total	2792

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Terraform Apply on x-pack/metricbeat/module/aws

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Terraform Apply on x-pack/metricbeat/module/aws

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• Description: terraform apply -auto-approve

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Test stats 🧪

Test	Results
Failed	0
Passed	2287
Skipped	505
Total	2792