EntryGenerator DefaultValues (1): Support for primitive Types & Enums

[chippmann]

Implement default value support for primitiveTypes (expect array which are considered primitive in this case as well).

This includes the following:

• Int
• Long
• Float
• Double
• String
• Boolean
• Enums

The user would have to write the following:

@RegisterProperty
var int = 100

@RegisterProperty
var long = 100L

@RegisterProperty
var float = 1.0f

@RegisterProperty
var double = 2.0

@RegisterProperty
var str = "hello"

@RegisterProperty
var bool = true

@RegisterProperty
var enum = TestEnum.ENUM1

Implementation hints:

• Files that need to be changed: PropertyDefaultValueProvider and PropertyHintTypeMapper
• Provide proper error messages (with Expcetions for now. MessageCollector will be implemented later)
• Default values need to be wrapped in a Variant
• A value type hint needs to be supplied at registration time
• Registration should look like:

property("nameOfProperty", TestingClass::propertyReference, STRING /*This is the püroperty type*/, Variant("defaultValue") /*This is the default value*/, true /**visible in editor/, DISABLED /*RPCMode*/, GODOT_PROPERTY_HINT_GLOBAL_DIR /*hint type*/, "" /*hint string*/)