Add filename generation

[olivervogel]

// create random filenames
$filename = FileExtension::GIF->filename(); // "bbf65ab32551e01e1647e11da254f052.gif"
$filename = Format::WEBP->filename(); // "762694f0c6be6642156bf4d27e08e6de.webp"
$filename = MediaType::IMAGE_JPEG->filename(); // "1314c05c6205243d468e7a9899d83fd2.jpg"

// create custom filenames
$filename = FileExtension::GIF->filename('animation'); // "animation.gif"
$filename = Format::WEBP->filename('icon'); // "icon.webp"
$filename = MediaType::IMAGE_JPEG->filename('avatar'); // "avatar.jpg"

[olivervogel]

Not in package scope.