Remove rigid body data structure from `Compound` #1656

Job	Run time
Bleeding Edge mosdef Tests for mBuild	3m 15s
mBuild Tests (macOS-latest, 3.9)	10m 45s
mBuild Tests (macOS-latest, 3.10)	8m 25s
mBuild Tests (macOS-latest, 3.11)	6m 48s
mBuild Tests (macOS-latest, 3.12)	9m 56s
mBuild Tests (macOS-13, 3.9)	20m 45s
mBuild Tests (macOS-13, 3.10)	15m 23s
mBuild Tests (macOS-13, 3.11)	18m 7s
mBuild Tests (macOS-13, 3.12)	24m 18s
mBuild Tests (ubuntu-latest, 3.9)	10m 36s
mBuild Tests (ubuntu-latest, 3.10)	8m 44s
mBuild Tests (ubuntu-latest, 3.11)	7m 32s
mBuild Tests (ubuntu-latest, 3.12)	9m 49s
mBuild Tests (windows-latest, 3.12)	16m 42s
Build Docker Image	0s
	2h 51m 5s

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