Add info about builtin configuration profile menu

**Your Godot version:**

4.2-4.3

**Issue description:**

I read the pages about compiling my custom exporting templates but there I found how to create my custom `.py` file which will configure what is necessary to compile and what no but then I knew about builtin UI menu `Project --> Customize Engine Build Configuration`. I knew about it from [godot forum](https://forum.godotengine.org/t/how-do-i-use-build-configuration-profiles-in-godot-4/2671) and think it should be added to the docs somewhere if it isn't there now (I tried to find it in the docs but failed. Maybe I overlooked...)

**URL to the documentation page (if already existing):**

https://docs.godotengine.org/en/stable/contributing/development/compiling/optimizing_for_size.htm

https://docs.godotengine.org/en/stable/contributing/development/compiling/index.html