pluto: add proxy support for FIPS

[jpculp]

Issue number:
Related: bottlerocket-os/bottlerocket#1667

Description of changes:

Replaces hyper-proxy with hyper-http-proxy.

Adds support for hyper client creation using a custom HTTP connector in aws-smithy-experimental.

Testing done:

Launched two instances (one built fips and one not) with the following network configuration:

[settings.network]
https-proxy = "<my-proxy>:8888"

Checked proxy server logs and found all traffic from my private IP being tunneled, including the EKS API calls for DescribeCluster.

In CloudTrail, I could see that the DescribeCluster API call source IP was my proxy server:

    "eventTime": "2024-10-23T23:15:56Z",
    "eventSource": "eks.amazonaws.com",
    "eventName": "DescribeCluster",
    "awsRegion": "us-west-2",
    "sourceIPAddress": "<my-proxy>",
    "userAgent": "aws-sdk-rust/1.3.3 os/linux lang/rust/1.81.0",

Testing notes:

If you want to test this on your own, here are a couple of hints:

• I used tinyproxy for this PR, but squidproxy will also work as I used it for testing pluto: Add hyper-proxy as a module bottlerocket#3439.
• In the tinyproxy config, uncomment the LogFile line and add your EKS cluster's IP range to Allow.
• It makes things a little easier to put the proxy in the same VPC/securitygroups as your EKS nodegroups. Then you can set settings.network.https-proxy to your EC2 host's private IP DNS name and proxy port.

Terms of contribution:

By submitting this pull request, I agree that this contribution is dual-licensed under the terms of both the Apache License, version 2.0, and the MIT license.

[jpculp]

Based on #173.

[jpculp]

Rebased and ready for review.

[jpculp]

Moved proxy logic from pluto::proxy to aws-smithy-experimental::hyper_1_0.

[jpculp]

• Added list of modified .rs files to COPYRIGHT.
• Rebased.