Add support for adding multiple media from base64 encoded strings

[alphaolomi]

Currently, the InteractsWithMedia trait only supports adding a single media file from a base64 encoded string. However, it would be convenient/useful to have the ability to add multiple media files from base64 encoded strings in a single call. Mostly for projects that extensively utilize base64 file uploads.

Proposing adding addMultipleMediaFromBase64

Usage example 1:

$post = Post::find(1);

$base64Media = [
    'image1.png' => 'base64 encoded string for image 1',
    'image2.png' => 'base64 encoded string for image 2',
    'image3.png' => 'base64 encoded string for image 3',
];

$post->addMultipleMediaFromBase64($base64Media);

Proposed function signature

/**
 * Add multiple base64 encoded files to the media library.
 *
 * @param array $base64data
 * @param string|array ...$allowedMimeTypes
 *
 * @throws InvalidBase64Data
 * @throws \Spatie\MediaLibrary\MediaCollections\Exceptions\FileCannotBeAdded
 *
 * @return \Spatie\MediaLibrary\MediaCollections\FileAdder
 */
 public function addMultipleMediaFromBase64(array $base64data, ...$allowedMimeTypes): FileAdder

Open to ideas 💡

[parallels999]

Hi, feel free to make a PR for review