Dynamic Multiplier for Sacrifice and other costs

[Hanmac]

currently it might be done via SVars, but i would like a more dynamic approach for Sacrifice Info.

• Like Jadar, Ghoulcaller of Nephalia would make decayed creature more likely to be sacrificed to other effects
• Oni-Cult Anvil makes Artifacts more likely to be sacrificed doing your turn.

The best way would be if the AI could get that info from the Triggers alone, especially for triggers only once like the Anvil. But i don't think AI is intelligent enough for this.

See #362 for cleanup of the SVars via timestamp.