build: pass correct defs and include path to moc

To make sure the right slots are generated, MOC needs -DHAVE_CONFIG_H
and correct include path to include bitcoin-config.h.
GUI for --disable-wallet compiles and -disablewallet mode

There is not much in the GUI to be done without wallet,
though it's possible to change options, watch the sync process,
and use the debug console.

So embed the debug console in the main window.