Remove worker/observer

Can remove a worker/observer at shoot/<id>/config.
Deleting a worker on a Shoot will also clean this Shoot's images for any work the user might have done before the deletion
Jobs update

Can update a job with a new user
css
moar css/html
Can delete an image
css/version
css/alert
image delete alert
Fix image not instantly showing after file upload
nerdier http errors
Fix file upload
Merge pull request #1 from bulgr0z/v0.2.1

V0.2.1