Get upload image link from widget

[Delaney]

Summary

Adds feature to send the image link gotten from uploading via the JS widget to a specified controller action

Ticket Link

Fixes https://github.com/cloudinary-devs/cloudinary-laravel/issues/95

[Delaney]

Hey @unicodeveloper could you please review this?

[colbyfayock]

@Delaney congrats on the merged PR! since it's officially October, you've always qualified for Hacktoberfest swag! please email hacktoberfest@cloudinary.com with your github username and a link to your contribution where I'll follow up to request more information for getting you your swag

https://cloudinary.com/blog/hacktoberfest-celebrate-open-source-sdks