Bind the String::humanize_size method

[Xrayez]

As suggested in #31993:

We could also consider exposing this method to scripts, so that projects that need to display file sizes can use it directly.

Exactly my use case. I want to compare different compression methods more easily.

The method signature is also changed to use uint64_t instead of size_t for it to be Variant-compatible: #32546 (comment).

[Xrayez]

Fails on macOS according to Travis:

core/variant_call.cpp:287:2: error: conversion from 'const Variant' to 'size_t' (aka 'unsigned long') is ambiguous
        VCALL_LOCALMEM1R(String, humanize_size);

These two would resolve this I think, but they're not compiled by default it seems:

godot/core/variant.h

Lines 175 to 178 in 82b9557

	#ifdef NEED_LONG_INT
	operator signed long() const;
	operator unsigned long() const;
	#endif

iphone platform does include this NEED_LONG_INT flag:

godot/platform/iphone/detect.py

Line 115 in b0d4184

env.Append(CPPDEFINES=['NEED_LONG_INT'])

[akien-mga]

I'd just change humanize_size to use uint64_t.

[akien-mga]

Thanks!

[aaronfranke]

What's the reason for NEED_LONG_INT existing? Isn't long long almost always 64-bit and int almost always 32-bit? This code existed before Godot was open source, so cc @reduz