Use PostgreSQL instead of Redis for taskmanager's persistence

[bamthomas]

Is your feature request related to a problem? Please describe.

For now the task manager uses a Redis Hashmap for storing tasks.
It can be cumbersome as, each time we change the structure it breaks the display of the tasks.
So tasks must be migrated.

Describe the solution you'd like

For persistence data in datashare (other that session data) we store it in the PostgreSQL database.
The schemas are migrated with liquibase.