Implement session.uploadprogress when supported in Drupal 8

[andrewholgate]

Apache Upload Progress is not yet available for PHP7 as it needs to be installed via PECL.

Find an alternative way to install it or add an alternative to the Upload Progress module.

[andrewholgate]

Uploadprogress will be deprecated soon and will not be available for PHP7.

We should wait for session.uploadprogress support in Drupal 8