Rollup node: plug store garbage collection in node GC function
Context
This MR makes the rollup node do a store GC at the same time it does a context GC, effectively implementing the whole GC.
Depends on !10135 (merged) and !10237 (merged).
Manually testing the MR
dune exec tezt/tests/main.exe -- -f sc_rollup.ml gc
Edited by Alain Mebsout