WIP: feat(doc): Add a doc for beginners #1961

Job	Run time
build_system	19s
duplicates	3s
build (gcc-13.deb, --mini-tests)	5m 36s
build (gcc-13.deb, --std-tests)	5m 50s
build (gcc-13.deb, --test-libcore)	13m 31s
build (gcc-13.deb, --extended-rand-tests)	8m 36s
build (gcc-13.deb, --extended-regex-example-tests)	6m 10s
build (gcc-13.deb, --extended-regex-tests)	11m 20s
build (gcc-13.deb, --test-successful-rustc --nb-parts 2 --current-part 0)	11m 15s
build (gcc-13.deb, --test-successful-rustc --nb-parts 2 --current-part 1)	11m 30s
build (gcc-13.deb, --projects)	16m 54s
build (gcc-13-without-int128.deb, --mini-tests)	6m 5s
build (gcc-13-without-int128.deb, --std-tests)	6m 5s
build (gcc-13-without-int128.deb, --test-libcore)	14m 14s
build (gcc-13-without-int128.deb, --extended-rand-tests)	9m 50s
build (gcc-13-without-int128.deb, --extended-regex-example-tests)	6m 36s
build (gcc-13-without-int128.deb, --extended-regex-tests)	12m 6s
build (gcc-13-without-int128.deb, --test-successful-rustc --nb-parts 2 --current-part 0)	11m 13s
build (gcc-13-without-int128.deb, --test-successful-rustc --nb-parts 2 --current-part 1)	11m 39s
build (gcc-13-without-int128.deb, --projects)	17m 54s
	3h 6m 46s

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