Boa: Refactoring `Property` flags

[HalidOdat]

Make the flags instead of Option we combine all the flags into one u8 and store and access the bits this should shrink the size of Property.

[Razican]

For the flags, we can use bitflags, as we do with the regex lexer.

[jasonwilliams]

The spec has the concept of a default property which we can surface with Default:
https://tc39.es/ecma262/#table-default-attribute-values

[jasonwilliams]

Make Accessor getter and setter store a Function instead of Value because there always going to be functions

I don't think this will work because those functions are exposed to the outside world, so if someone does a typeof check it would fail.

const object1 = { property1: 42 };
Object.defineProperty(object1, 'prop2', { get: () => {return "blah"}});
typeof Object.getOwnPropertyDescriptor(object1, 'prop2').get; // function