[5.3] Handle validating failed file uploads

[themsaid]

This PR is an attempt to deal with these issues: #8203, #4467, #4226 and many other duplicates.

The problem:
When uploading files greater than upload_max_filesize all validation rules related to file validation fails due to the file being invalid. Also a required validation rule will return false so the user will get "The file is required" even though he did attach a file to the form.

The suggested solution:
While validating each rule we check if the value is a file that failed to upload isValid()===false and that a rule that imply the field is required or is a file was being used. If that's the case we cause the validation to fail with a message file_uploaded, this message will have a translation line in the language files and the output will be The image uploading failed..

This behaviour will indicate a generic upload failure instead of showing a validation error that's not related to the actual problem.