Add support for inertia deferred props

[matthiasweiss]

Hello 👋

I've drafted up an initial version of support for inertia v2 deferred props.

Usage looks like this:

class AutoDeferredData extends Data
{
    #[AutoInertiaDeferred]
    public InertiaDeferred $deferred;
}

$data = AutoDeferredData::from(['string' => Inertia::defer(fn () => 'Deferred Value')]

I'm not really happy with the implementation, since the concept of deferred props is technically not related to lazy properties, but the implementation is basically copied 1:1. On the other hand, this kind of makes sense, since the effects of lazy and deferred properties are very similar.

My other approach would've been to basically copy the structure of the abstract Lazy, AutoLazy & InertiaLazy classes, but this would've required a bunch more changes.

However, I still don't really like how I've done it here, but I don't think this can be done a lot better without larger refactoring. Maybe a bigger refactoring even makes sense, since merging props should also be implemented.

I'm definitely open for any suggestions!

Best,
Matthias

[matthiasweiss]

This is mixed instead of DeferProps', since the $valueparameter in theAutoInertiaDeferred::build` method is mixed and needs to be passed to this function