Review 2.11 data migration script

[tcompa]

$ fractalctl update-db-data
**WARNING**
This command acts directly on database data. If you have any doubt about this, do not run it!

Expected use case:
You have updated fractal-server from some old version to a target version, and now need to fix some database data.
The detected target version is '2.11.0a2' (corresponding to the update-db-data module '2_11_0.py').
Note that the old and target versions MUST be consecutive, that is, you cannot skip an intermediate version.
The list of released versions is available at https://github.com/fractal-analytics-platform/fractal-server/blob/main/CHANGELOG.md.

Do you confirm that the old and target versions are consecutive? (yes/no)
yes
Do you confirm that the target version is 2.11.0a2? (yes/no)
yes
Have you run 'fractalctl set-db' with the target version? (yes/no)
yes
Have you made a backup of your database (e.g. via `pg_dump`)? (yes/no)
yes
Are you sure you want to proceed? (yes/no)
yes
OK, now starting data-migration script

I would expect:

1. INFO logs being shown (likely through logging.basicConfig(logging.INFO)
2. A log that says START and a log that says END.

[ychiucco]

Closed with 9797196