gnd: Support multiple subgraphs, grafting, subgraph composition in dev mode #9764

Job	Run time
Run integration tests	5m 56s
Clippy linting	1m 31s
Subgraph Runner integration tests	4m 30s
Build in release mode	2m 6s
Check rustfmt style	9s
Run unit tests	12m 21s
	26m 33s

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