feat: better epoll detection, allow to disable epoll

[StarpTech]

Motivation and Context

This PR enables users to disable EPOLL support. In addition, we improved EPOLL support detection by a real integration test. In practice, users won't need to disable it manually anymore. I tested it manually on docker with limited host capabilities.

I also get rid of the terms EPOLL and KQUEUE in the configuration because they depends on the operating system. We abstract them away.

Breaking changes

The following internal engine flags (including their ENV equivalent) have been renamed for clarity.

EnableWebSocketEpollKqueue => EnableNetPoll
EpollKqueuePollTimeout => WebSocketClientPollTimeout
EpollKqueueConnBufferSize => WebSocketClientConnBufferSize
WebSocketReadTimeout => WebSocketClientReadTimeout

Requires: wundergraph/graphql-go-tools#984

Checklist

• I have discussed my proposed changes in an issue and have received approval to proceed.
• I have followed the coding standards of the project.
• Tests or benchmarks have been added or updated.
• Documentation has been updated on https://github.com/wundergraph/cosmo-docs.
• I have read the Contributors Guide.

[Aenimus]

The tag release you reference doesn't have a package that is used somewhere in Cosmo according to the failed CI.

[StarpTech]

The tag release you reference doesn't have a package that is used somewhere in Cosmo according to the failed CI.

This is fine because we haven't released the engine yet.

[Aenimus]

The tag release you reference doesn't have a package that is used somewhere in Cosmo according to the failed CI.

This is fine because we haven't released the engine yet.

Ah, you were using replace with your local branch? But then should this PR be a draft?

[StarpTech]

Ah, you were using replace with your local branch? But then should this PR be a draft?

Yes, could be, but it was ready to review. I was only waiting for the engine release.

[Aenimus]

LGTM; I believe CI will be fine upon engine tag update.