Remove duplicate editor settings definitions

[KoBeWi]

I noticed that EDITOR_DEF is overused in many places. This is a very bad idea, because each time you use EDITOR_DEF, a cat starts crying somewhere you need to provide a default value. This leads to some ridiculous situations like a default value repeated 7 times. The actual value then depends on initialization order. Luckily I spotted only one setting that had inconsistent defaults across definitions.

My absolute favorite was this:

Same thing, defined twice few lines apart.

I went over the codebase and cleaned it up by removing duplicate defs of the same settings and changing them to EDITOR_GET. We have most of the settings defined in _load_defaults() method of EditorSettings, so if there were some additional EDITOR_DEFs, I left the ones in the singleton. Then I left stuff defined in a constructor over inlined settings. If some settings were on equivalent level (i.e. not apparent which one comes first), I moved the definition to _load_defaults().

We should have some policy for using EDITOR_DEF. Repeating defaults multiple times can lead to errors, but also IMO it's just dumb xd

Another things to consider could be:

• moving all editor setting definitions to _load_defaults(), so they are all in one place
• changing all usage of EditorSettings::get_singleton()->get() to EDITOR_GET (it's the same thing, except it displays error when setting is missing and also it's much shorter)

Also Project Settings likely need the same treatment.

[EricEzaM]

• moving all editor setting definitions to _load_defaults(), so they are all in one place

Yeah I have proposed this a couple of times but there was some push back from reduz I think. This is also relevant to this proposal/issue godotengine/godot-proposals#1339 (comment)

[akien-mga]

Thanks!