Particle prefab parent

[NotGaylien]

Pull Request

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Summary

Allows particle prefabs to parent to hit object and follow them.

Motivation & Context

Using prefabs to spawn decals / sub particle effects on moving objects, like players and cars.
this allows me to ensure they will stick to them.

Fixes: #10387

Implementation Details

Particle

• now includes hit body reference

ParticleEffect

• CollisionPrefab struct now includes physics body for the hit body
• Bool to enable parenting in prefab feature
• absolute position not true when this is enabled

Screenshots / Videos (if applicable)

BEFORE / with it disabled.

sbox-dev_Pp7p8GkaLA.mp4

AFTER

sbox-dev_0sPLg2FwsQ.mp4

Checklist

• Code follows existing style and conventions
• No unnecessary formatting or unrelated changes
• Public APIs are documented (if applicable)
• Unit tests added where applicable and all passing
• I’m okay with this PR being rejected or requested to change 🙂