Add 'simple media bulk upload' to core

[willguv]

Some councils have installed https://www.drupal.org/project/simple_media_bulk_upload to speed up loading of multiple media files

@benhillsjones has used it in Haringey and rates it, was installed by Annertech

Let's install it on Prod and try it out

[willguv]

I'll try doing this with my new gitpod set up @stephen-cox

[willguv]

@stephen-cox with the help of @finnlewis I got this running and have taken it for a spin

Think it's very useful functionality and we should definitely include it as part of core, switched on

[markconroy]

@willguv I have a PR for this now #729

[willguv]

Wow! Thank you @markconroy