Add usability features to migration scripts

Especially while migrating large databases, the scripts have no user feedback implemented. If the data warehouse host interrupts there will be no feedback. Additionally it is helpful to have a approximation of calculation time.

## Task: Add a loading feature

Display loading progresses for each individual step and
display the overall progress (search for a progress marker that works for postgres as well)

There are apt libraries that can be used, like **pv (pipe viewer)**, to show progress by file size:
```
# install pipe viewer
sudo apt-get install pv

# example usage
sudo docker exec -i "$docker_db_container" \
bash -c "pv /backup/backup_i2b2.sql | psql -U postgres -d i2b2 -q"
```