Allow control over log channels captured/displayed by CLI

What's the problem this feature will solve?

My application emits a lot of logs. I'd like to view only a certain channel or channels when I specify e.g. --log-level=debug in the pytest CLI.

Describe the solution you'd like

It would be nice to be able to specify --log-channel=myapp.a.b one or more times to display only certain channels. The default could be --log-channel=* to display everything, but, if a non-default value is given, only the specified channels should be emitted to the console.

This would allow me to filter out log noise from irrelevant channels, especially at the debug level of my application, when trying to debug a specific failing test.

Alternative Solutions

I've not thought of any other solutions. I could add a log handler to my code directly, but that would defeat the purpose of configuring this on-demand via the CLI.

Start by tracing pytest's CLI handling for --log-level and the logging capture/display path. Review the existing logging-related tests and determine how repeated --log-channel values should interact with the default behavior. Done means selected channels are displayed through the CLI while unrelated channels are filtered, with coverage for default and explicit channel selections.