Cherry-pick #23335 to 7.x: Fix types for response fields of kubelet api

[ChrsMark]

Cherry-pick of PR #23335 to 7.x 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]

💚 Build Succeeded

the below badges are clickable and redirect to their specific view in the CI or DOCS

Expand to view the summary

Build stats

• Build Cause: Pull request #23383 updated

• Start Time: 2021-01-07T08:33:24.814+0000

• Duration: 54 min 52 sec

Test stats 🧪

Test	Results
Failed	0
Passed	2287
Skipped	505
Total	2792

Steps errors

Expand to view the steps failures

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

• Took 0 min 14 sec . View more details on here
• Description: terraform apply -auto-approve

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

• Took 0 min 15 sec . View more details on here
• Description: terraform apply -auto-approve

💚 Flaky test report

Tests succeeded.

Expand to view the summary

Test stats 🧪

Test	Results
Failed	0
Passed	2287
Skipped	505
Total	2792