depends: only use D-Bus with Qt on linux
Summary:
Since #8210 we've been passing -dbus-runtime when configuring Qt, however D-Bus isn't used on macOS or Windows. So rather than blanket passing -dbus-runtime, only use D-Bus when building for linux, and disable it for Windows and macOS. This also saves some time building qt in depends (for windows or macOS).
Backport of core PR17521.
Depends on D5679.
Test Plan: Run the Gitian builds.
Reviewers: #bitcoin_abc, deadalnix
Reviewed By: #bitcoin_abc, deadalnix
Differential Revision: https://reviews.bitcoinabc.org/D5680