prefab spawning ability

[poetahto]

This is a generic ability for spawning objects where the mouse is positioned.

We can reuse this for several similar monster abilities, like...

• Earth Wall Block
• Rock Platform / Stairs
• rain / hail
• water geyser
• whirlpool
• lava pool spawn
• fire rain

In order to support all these abilities, the ability should do the following:

1. Expose an AssetReference to the inspector, so some prefab can be assigned.
2. Expose an action point cost variable to the inspector
3. Expose a max range variable to the inspector
4. When the player uses left click, instantiate the prefab at the current mouse position and spend the action points.
5. Ensure that the distance between the mouse position and the user is clamped to max range.