kernel: Pass interrupt reference to chainman

This and the following commit seek to decouple the libbitcoinkernel
library from the shutdown code. As a library, it should it should have
its own flexible interrupt infrastructure without relying on node-wide
globals.

The commit takes the first step towards this goal by de-globalising
`ShutdownRequested` calls in kernel code.

Co-authored-by: Russell Yanofsky <russ@yanofsky.org>
Co-authored-by: TheCharlatan <seb.kung@gmail.com>

src/bitcoin-chainstate.cpp

@@ -113,7 +113,7 @@ int main(int argc, char* argv[])
         .chainparams = chainman_opts.chainparams,
         .blocks_dir = abs_datadir / "blocks",
     };
-    ChainstateManager chainman{chainman_opts, blockman_opts};
+    ChainstateManager chainman{kernel_context.interrupt, chainman_opts, blockman_opts};
 
     node::CacheSizes cache_sizes;
     cache_sizes.block_tree_db = 2 << 20;