Add count media functionality

[salamwaddah]

I would like to add countMedia as a fluent alternative to

• count($this->getMedia($collectionName, $filters))
• $this->getMedia($collectionName)->count();

Here's my use case in blade

// before
@if($model->getMedia()->count() > 1)
@endif

// after
@if($model->countMedia() > 1)
@endif

A similar PR #1582 closed 5 years ago but I wish this is reconsidered

[freekmurze]

Thanks, but I'm going to pass on this to keep the package simple.