Add events for file classification inputs

[Olie-Chanz]

We just migrated from Vue 2 to Vue 3 and that also means migrating our vue-formulate to formkit.

There are certain events that we used to show progress / loading state when uploading a file on a file input field where as: @file-upload-progress, @file-upload-complete, @file-upload-error, @file-removed. But these seems to be not available in FormKit. Is this something planned in the future?

[justin-schroeder]

We are planning to have a much more comprehensive file uploader in the pro package in the future. The file input itself (in FormKit) is intended to more closely mirror a native file input rather than the highly-opinionated file input in Vue Formulate (which was awesome, but perhaps was a bit too opinionated for the "base" file input).