[Bug] Improve migration

[To-om]

Request Type

Bug

Work Environment

TheHive 4.0.0-1

Problem Description

The aim of this issue is to solve 3 migration related problems:

• Migration tool check if alert exists before create it. This is useless and slow down alert creation.
• The estimation count of elasticsearch entities doesn't work because [size] cannot be [0] in a scroll context
• The first case creation is very long because is search user profile using a full scan.