Add max capacity configuration for embedded Jetty QueuedThreadPool

[onobc]

We are replacing our legacy in-house Java application framework with Spring Boot. The last missing feature parity is the ability to constrain Jetty's backing queue.

Issue #8662 was the same issue from a couple years back. It landed on this comment from @wilkonsa

A pull request that adds this configuration option for Jetty, Tomcat, and Undertow would be welcome.

However, the issue ended up closing due to inactivity. I intend to submit that PR.

[snicoll]

@Bono007 thanks but there is no need to create an issue and a PR as one supersedes the other.

Closing in favour of PR #19494

[onobc]

Got it.
I was curious about that @snicoll . In the case where I go straight to a PR I just skip the "Closes gh-abc" text in the commit message I am assuming,

[snicoll]

The commit message of a PR we process is almost always rewritten. We rewrite the closes if pressent as the issue is closed (like here) and we use the PR issue id as the reference in the commit message.