Implements post-process film grain effects #73992

Job	Run time
toml	6s
ci	4m 17s
miri	8m 45s
check-doc	8m 44s
typos	8s
build (ubuntu-latest)	8m 45s
build (macos-latest)	8m 48s
build (windows-latest)	8m 34s
check-missing-examples-in-docs	38s
check-bevy-internal-imports	9s
check-release-content	38s
check-missing-features-in-docs	34s
markdownlint	1m 34s
check-compiles-no-std	0s
check-compiles-no-std-examples	0s
check-compiles	0s
check-compiles-no-std-portable-atomic	0s
msrv	1s
build-wasm-atomics	1s
build-wasm	1s
	51m 43s

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