Introduce `MastForestStore` #4858

Job	Run time
Clippy	1m 12s
Test Rust stable on ubuntu with --profile test-release	10m 18s
no-std (stable, wasm32-unknown-unknown)	1m 37s
Test Rust stable on ubuntu with --profile test-release --doc	5m 50s
Check Rust stable on ubuntu with --all-targets --no-default-features	1m 14s
no-std (nightly, wasm32-unknown-unknown)	1m 29s
Test Rust nightly on ubuntu with --profile test-release	10m 8s
rustfmt	13s
Check Rust stable on ubuntu with --all-targets	1m 7s
Test Rust nightly on ubuntu with --profile test-release --doc	5m 48s
Check Rust stable on ubuntu with --all-targets --all-features	1m 19s
Test Rust nightly on windows-2022	0s
Check Rust nightly on ubuntu with --all-targets --no-default-features	1m 13s
Check Rust nightly on ubuntu with --all-targets	1m 12s
Check Rust nightly on ubuntu with --all-targets --all-features	1m 18s
	43m 58s

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