Demon invasion.

Campaign file updated.

Changes:

- In the first mission, the composition of neutral creatures and artifacts has been changed (randomness removed at the start), and additional objects have been added at the start (mentor, garrisons).
- In the second mission, randomness has been removed from some artifacts, and the armies of some heroes have been changed.
- In the fourth mission, the cutscenes are played again at the end.
- In the fifth mission, the "Summon Ship" spell has been added to the Necromancers.
- The icons of the added heroes have been adjusted.