feature: support for polymorphic relations

[mr-feek]

Basic support for polymorphic relations, should close #80 cc @brendt

It isn't smart enough to figure out MorphTo models, I'm just leaving that as mixed for now. Feel free to pr that functionality!

[brendt]

Thanks! It seems to have fixed one of the errors I encountered, but these other three still exist:

ERROR: TooManyTemplateParams - app/Context/Product/Models/Concerns/HasProductAttributes.php:12:16 - Illuminate\Database\Eloquent\Relations\MorphToMany<App\Context\Product\Models\ProductAttribute> has too many template params, expecting 0 (see https://psalm.dev/184)
        return $this->morphToMany(
            ProductAttribute::class,
            'assigned_attribute',
            'product_assigned_attributes',
            'assigned_attribute_uuid'
        );


ERROR: TooManyTemplateParams - app/Context/Product/Models/FieldOfStudy.php:26:16 - Illuminate\Database\Eloquent\Relations\MorphToMany<App\Context\Product\Types\Event\Models\Event> has too many template params, expecting 0 (see https://psalm.dev/184)
        return $this->morphedByMany(Event::class, 'product');


ERROR: TooManyTemplateParams - app/Context/Product/Models/ProductAttribute.php:23:16 - Illuminate\Database\Eloquent\Relations\MorphToMany<App\Context\Product\Types\Event\Models\Event> has too many template params, expecting 0 (see https://psalm.dev/184)
        return $this->morphedByMany(
            Event::class,
            'assigned_attribute',
            'product_assigned_attributes'
        );

[brendt]

Let me know if you need a more comprehensive code snippet.

[mr-feek]

Ah I forgot MorphToMany, gimme a few mins to push up a fix!

[njaremko]

This is missing MorphOne support too :)