[WIP] Skylights and other fragile terrain break when creatures step on them

[Consoleable]

Summary

Content "Skylights break when stepped on"

Purpose of change

I saw that the skylight JSON had a todo about this

Describe the solution

added function in creature.cpp and creature.h, as well as a terrain tag to mapdata, and the associated tag in skylight.
Now anyone can make breakable terrain by adding the fragile tag to terrain json and using the appropriate bash values.

Describe alternatives you've considered

TBD

Testing

TODO

• monsters of human weight break skylights when stepping on them
• players of average weight break skylights when stepping on them
• npcs break skylights when stepping on them
• players who are prone do less damage to fragile terrain
• intelligent monsters have a chance to avoid obvious fragile terrain
• npcs avoid obviously fragile terrain unless they have no option
• npcs forced to walk on fragile terrain do so prone Not planned
• add thin ice that can collapse, to be added in mapgen in later PR
• make vehicles damage fragile terrain based on vehicle weight and number of wheels
• add pit traps
• make friendly npcs avoid walking on player placed pit traps
• player warnings for fragile tiles that are transparent or player made
• fix smashing terrain objects results in incorrect terrain underneath #83653 otherwise it won't work
• fix Digging out pits no longer makes a dirt terrain at the bottom #83781 because reasons

Additional context

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[ehughsbaird]

I know this is a draft, but you can delete commented out code. It remains in the git history if you need it.

[Blueflowerss]

If moving onto the fragile terrain would cause it to collapse, the player should get a query about wanting to proceed.

[Consoleable]

If moving onto the fragile terrain would cause it to collapse, the player should get a query about wanting to proceed.

yeah it's on my list, thought it was on the list here, i'll add it