tree-sitter: introduce tree-sitter, add nix grammar #1452

Job	Run time
nix-build-develop-clang (none, release, true)	5m 45s
nix-build-develop-clang (none, release, false)	5m 2s
nix-build-develop-clang (none, debug, true)	3m 55s
nix-build-develop-clang (none, debug, false)	5m 13s
nix-build-develop-gcc (none, release, true)	6m 43s
nix-build-develop-gcc (none, release, false)	5m 38s
nix-build-develop-gcc (none, debug, true)	6m 7s
nix-build-develop-gcc (none, debug, false)	4m 20s
nix-build-develop-gcc (undefined, release, true)	10m 24s
nix-build-develop-gcc (undefined, release, false)	11m 9s
nix-build-develop-gcc (undefined, debug, true)	5m 34s
nix-build-develop-gcc (undefined, debug, false)	7m 28s
	1h 17m 18s

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