fix: Set IdleTimeout for http.Server

[mannbiher]

Description

What this PR does / why we need it:

Setup IdleTimeout for ratify http server

Which issue(s) this PR fixes (optional, using fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when the PR gets merged):

Fixes #1416

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

Yes. I tested this change on an EKS cluster with OPA gatekeeper. Without an idle timeout, gatekeeper audit controller keeps creating new connections till it reaches the OS limit and then any new connection fails. After the change, gatekeeper audit controller still creates new requests, but the connections are short-lived and I no longer encounter the error.

Please describe the tests that you ran to verify your changes. Please also list any relevant details for your test configuration

• Manually verified number of connections to ratify using ss command on gatekeeper-audit container using ephemeral debug container

Checklist:

• Does the affected code have corresponding tests?
• Are the changes documented, not just with inline documentation, but also with conceptual documentation such as an overview of a new feature, or task-based documentation like a tutorial? Consider if this change should be announced on your project blog.
• Does this introduce breaking changes that would require an announcement or bumping the major version?
• Do all new files have appropriate license header?

Post Merge Requirements

• MAINTAINERS: manually trigger the "Publish Package" workflow after merging any PR that indicates Helm Chart Change

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 1 lines in your changes are missing coverage. Please review.

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Files	Patch %	Lines
httpserver/server.go	0.00%	1 Missing ⚠️

Additional details and impacted files

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  Misses         ?     1622           
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[binbin-li]

@mannbiher thanks for investigating and fixing it! @susanshi @akashsinghal do you think it would be beneficial to configure it to handle varying levels of load in the future?

[akashsinghal]

@mannbiher thanks for investigating and fixing it! @susanshi @akashsinghal do you think it would be beneficial to configure it to handle varying levels of load in the future?

Potentially. I think the idle timeout is one factor among others for higher request counts. We'd only be able to determine after another round of perf testing and that too perf testing that can run for longer period of time. My opinion would be to proceed forward with a set default right now like PR is doing and we can revisit if this becomes a concern in the future.