[GraphQL][DotMove][3/n] Adds `External` resolver #74024

Job	Run time
diff	8s
license-check	1m 14s
release-notes-check	17s
move-auto-formatter-ci-test	0s
test (ubuntu-ghcloud)	28m 9s
simtest	13m 46s
test-extra (ubuntu-ghcloud)	10m 0s
windows-build (windows-ghcloud)	8m 36s
move-test	0s
clippy	3m 25s
rustfmt	21s
test	0s
test-extra	0s
cargo-deny (advisories, licenses, bans, ...)	40s
cutting a new execution layer	1m 27s
graphql-rpc	6m 8s
	1h 14m 11s

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