Implement `pallet-assets-freezer` #2075

Job	Run time
check-dependency-rules	9s
check-markdown	14s
check-workspace	18s
set-image	8s
fmt	1m 11s
check-rust-feature-propagation	1m 58s
check-umbrella	2m 18s
check-toml-format	1m 3s
test-rust-features	2m 11s
	9m 30s

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