Remove rigid body data structure from `Compound` #1655

Job	Run time
Bleeding Edge mosdef Tests for mBuild	3m 10s
mBuild Tests (macOS-latest, 3.9)	11m 23s
mBuild Tests (macOS-latest, 3.10)	7m 21s
mBuild Tests (macOS-latest, 3.11)	7m 33s
mBuild Tests (macOS-latest, 3.12)	9m 14s
mBuild Tests (macOS-13, 3.9)	22m 34s
mBuild Tests (macOS-13, 3.10)	16m 14s
mBuild Tests (macOS-13, 3.11)	20m 19s
mBuild Tests (macOS-13, 3.12)	22m 35s
mBuild Tests (ubuntu-latest, 3.9)	9m 35s
mBuild Tests (ubuntu-latest, 3.10)	8m 21s
mBuild Tests (ubuntu-latest, 3.11)	7m 35s
mBuild Tests (ubuntu-latest, 3.12)	9m 49s
mBuild Tests (windows-latest, 3.12)	15m 53s
Build Docker Image	0s
	2h 51m 36s

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