gui: Shortcut to close RPC Console

[cvengler]

Credits to promag.
Similar to #16515 with a macOS addition.

This PR makes it possible to close the RPC Console (like a terminal) with Ctrl+D. On macOS it will close with Ctrl+W as it is a more common syntax there.

[DrahtBot]

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Conflicts

Reviewers, this pull request conflicts with the following ones:

• qt: Add -guisettingsdir option #17636 (qt: Add -guisettingsdir option by emilengler)

If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.

[luke-jr]

Doesn't Ctrl-D work in macOS Terminal too?

I think it makes more sense to just do Ctrl-D here, and let the other PR add Ctrl-W too.

[cvengler]

Doesn't Ctrl-D work in macOS Terminal too?

Well yes but actually no
It terminates the shell process but the window remains open asying that the process was terminated successfully

[fanquake]

Going to close with the same rationale as #16515. This hasn't seen any renewed interest and I think the project has more important things to work on. Ideally all of this kind of thing would be handled by Qt.