Progress Bar

## Description

As a user, I would like to know the progress of my experiment after I started it.

## Solution

I suggest the implementation of a progress bar to help the users know how long till their experiment completes.

Based on stages of running an experiment we could implement individual progress bar as well, displaying status of individual stages.

For example:


## Tasks
- [ ] The progress information needs to be added to an experiment if it is
- [ ] The web controller requires a mapping from the experiment task id (or experiment configuration) to the currently existing experiment task objects.
- [ ] An experiment task object should offer a status information.
- [ ] According to the example above, several steps can be defined, each with a certain progress.
- [ ] The GUI has to be able to show the progress information to the user.