Limit blockexplorer versions to 1.x.y

Per semver semantics when blockexplorer 2.0.0 is released it will be
incompatible in some way with 1.x.y and thus should be opt in.

net/remote/remote-node.sh

@@ -194,7 +194,7 @@ local|tar)
     fi
 
     if [[ $nodeType = apinode ]]; then
-      npm install @solana/blockexplorer
+      npm install @solana/blockexplorer@1
       npx solana-blockexplorer > blockexplorer.log 2>&1 &
     fi
     ./multinode-demo/fullnode.sh "${args[@]}" "$entrypointIp":~/solana "$entrypointIp:8001" > fullnode.log 2>&1 &