GDScript: access level for class method and class variable

[zjin123]

Implement godotengine/godot-proposals#11039

[dalexeev]

• See also GDScript: Implement soft access restriction for members prefixed with _ and __ (as warning by default) #98557.

[Lazy-Rabbit-2001]

This is a superseding pr of #98136 as well, with extra stuff and access levels implemented.
Sorry but I cannot review yours, dunno why.
You have to rename your accessLevelToString() in snake_case, like access_level_to_string() to make your codes coherent in form with other parts, see DataType::to_string() and DataType::to_string_strict()

[zjin123]

This is a superseding pr of #98136 as well, with extra stuff and access levels implemented. Sorry but I cannot review yours, dunno why. You have to rename your accessLevelToString() in snake_case, like access_level_to_string() to make your codes coherent in form with other parts, see DataType::to_string() and DataType::to_string_strict()

Thanks for pointing out. I will fix the name.