Fix: CA does not work properly while using AWS EC2 IMDSv2

[darkpssngr]

This fixes #3592.
We use the aws sdk to fetch the metadata. The endpoint explicitly set to "http://169.254.169.254" so that tests don't fail.

We tested it by applying these changes in 1.18.3 and it worked fine. tested both scale up and scale down.

This was tested in instances with IMDsV1 enabled and disabled.

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[darkpssngr]

accepted CLA

[darkpssngr]

@Jeffwan @feiskyer could you please take a look at this? Not sure if something's pending from my end.

[darkpssngr]

@gjtempleton can you please take a look at this?

[gjtempleton]

Thanks for the PR.

I have one minor nit on expanding the docs, but other than that, this looks good.

[jaypipes]

Nice work on this @darkpssngr.

[jaypipes]

/approve
/lgtm

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[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: darkpssngr, jaypipes

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