Refine conda package dependencies, drop Rust minimum version #4181

Job	Run time
Check for upstream trigger phrase	2s
Test importing with bare requirements	12m 12s
Build & Test (ubuntu-latest, python: 3.8, distributed: false)	8m 39s
Build & Test (ubuntu-latest, python: 3.9, distributed: false)	8m 46s
Build & Test (ubuntu-latest, python: 3.10, distributed: false)	8m 56s
Build & Test (windows-latest, python: 3.8, distributed: false)	15m 38s
Build & Test (windows-latest, python: 3.9, distributed: false)	16m 0s
Build & Test (windows-latest, python: 3.10, distributed: false)	22m 30s
Build & Test (macos-latest, python: 3.8, distributed: false)	23m 24s
Build & Test (macos-latest, python: 3.9, distributed: false)	13m 50s
Build & Test (macos-latest, python: 3.10, distributed: false)	25m 35s
Build & Test (ubuntu-latest, python: 3.8, distributed: true)	8m 51s
Build & Test (ubuntu-latest, python: 3.10, distributed: true)	13m 31s
	2h 57m 54s

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