WIP: Don't disconnect API clients (HTTP) automatically (after 10s)

[Al2Klimov]

fixes #4968

[dnsmichi]

Unfortunately the proposed fix does not entirely solve the issue.

[Al2Klimov]

Does the error still occur?

[Stefar77]

Try with #5419

Making the timeout a config setting may be an idea.
edit;
Set mine to 1 hour;
`after more waiting it seems stable at 40 threads, I think the Netscaler montitor does keep-alive and my phone just sometimes is very slow closing connections.

Going to keep testing but I think the entire timer may be removed indeed.

[dnsmichi]

Entirely removing the timeout isn't an option here. Since this is what this patch is all about, I'm closing this in favor of a better solution to be discussed in #5148 and so on.