LibCore: Port SystemServerTakeover.cpp to Windows

[stasoid]

Requires #2946 (fails to compile on Linux w/o it)

[circl-lastname]

This isn't an issue with the PR, but the name take_over_socket_from_system_server definitely isn't accurate anymore since SerenityOS's SystemServer is a concept which doesn't apply to Windows or Linux.

I found that SOCKET_TAKEOVER is actually set by LibWebView when the UI process spawns WebContent

ladybird/Libraries/LibWebView/Process.cpp

Line 42 in 03ac6e6

TRY(Core::Environment::set("SOCKET_TAKEOVER"sv, takeover_string, Core::Environment::Overwrite::Yes));