Only set quicktune keybinds in debug builds

[rollerozxa]

This PR disables the default quicktune keybinds in non-debug builds, as the quicktune functionality is only useful for engine development in debug builds anyways and the keybinds interfere with other keybinds mapped onto the numpad. (i.e. I have keybinds on my numpad to start and stop recording with OBS, which also triggers quicktune)

To do

This PR is a Ready for Review.

How to test

See that quicktune keybinds exist in debug and not in release...

[SmallJoker]

I think it would make more sense to unbind the keys altogether for debug&release but document them in settingtypes.txt.

[sfan5]

I don't run debug builds for development so maybe do this for all non-release builds?
Doesn't matter that much though.

[Desour]

I don't run debug builds for development so maybe do this for all non-release builds?

Quicktune only works in debug builds, so this PR is consistent:

minetest/src/util/quicktune.h

Lines 83 to 95 in 1317cd1

	#ifndef NDEBUG
	#define QUICKTUNE(type_, var, min_, max_, name){\
	QuicktuneValue qv;\
	qv.type = type_;\
	qv.value_##type_.current = var;\
	qv.value_##type_.min = min_;\
	qv.value_##type_.max = max_;\
	updateQuicktuneValue(name, qv);\
	var = qv.value_##type_.current;\
	}
	#else // NDEBUG
	#define QUICKTUNE(type, var, min_, max_, name){}
	#endif

I agree it would be nice to enable quicktune independently of debug builds.

[TurkeyMcMac]

This way is fine for now, IMO.