Move ffi/gn to docs/tutorials/gn (#4535) #1480

Job	Run time
Check Credentials for jobs that need JSON credentials	3s
WASM Demo	4m 27s
bench-binsize	4m 51s
bench-memory (macos-latest)	19m 36s
bench-memory (ubuntu-latest)	7m 9s
bench-memory (windows-latest)	13m 0s
bench-datasize	15m 37s
bench-perf (components/collections)	4m 27s
bench-perf (components/datetime)	4m 33s
bench-perf (components/locid)	5m 14s
bench-perf (components/locid_transform)	2m 41s
bench-perf (components/plurals)	6m 16s
bench-perf (experimental/transliterate)	2m 39s
bench-perf (components/segmenter)	3m 46s
bench-perf (experimental/zerotrie)	5m 36s
bench-perf (provider/blob)	4m 20s
bench-perf (utils/fixed_decimal)	4m 4s
bench-perf (utils/litemap)	2m 20s
bench-perf (utils/tinystr)	6m 21s
bench-perf (utils/writeable)	3m 20s
bench-perf (utils/zerovec)	8m 21s
Rust docs	4m 32s
C++ docs	59s
Dart docs	1m 46s
TypeScript docs	48s
Deploy to GitHub Pages	13m 58s
	2h 30m 44s

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