Remove bug that causes stop events to create sessions

[eiffel777]

This PR fixes a bug in the CloudStateReconstructorTransformer that allowed end events such as Stop, Power Off or Shelve to start a new session. This is fixed by adding an if statement that prevents an end event from creating a new session.

A new openstack log file has been added for the regression tests. It is ingested separately to ensure we create a situation where sessions would have been incorrectly made before this change. This change means this data should not cause any new sessions to be made.

The migration script will look for sessions with end events, display the list of sessions to the user and ask if they want to remove the session. Re-aggregation of the cloud data is already necessary for upgrading to 9.0. Below is a screenshot of how this is displayed when running the upgrade.

Tests performed

Tested manually in docker and also added data to docker that would have created sessions before his issue was fixed.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project as found in the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.