Merge fort-nix/nix-bitcoin#504: Add fulcrum module

7d7f2df006 fulcrum: add module (Erik Arvstedt)
edd8bd311c bitcoind-rpc-public-whitelist: add `ping`, `help` (Erik Arvstedt)
f946a7cd9b examples: use `mkDefault` for setting `system.stateVersion` (Erik Arvstedt)
79994d0bd2 tests: increase postgresql startup timeout (Erik Arvstedt)

Pull request description:

ACKs for top commit:
  nixbitcoin:
    ACK 7d7f2df006

Tree-SHA512: 866f0a40bb81ceb2008e6efbd415eeee201b9e56aa5ebc60fd1bb4b6eda300155faaa2e6492d8145b3c6084b1e8ef5ec7d4e0ff694beb328d2e5ed755c9d04b4

modules/netns-isolation.nix

@@ -293,6 +293,10 @@ in {
       clightning-rest = {
         id = 30;
       };
+      fulcrum = {
+        id = 31;
+        connections = [ "bitcoind" ];
+      };
     };
 
     services.bitcoind = {
@@ -323,6 +327,8 @@ in {
 
     services.electrs.address = netns.electrs.address;
 
+    services.fulcrum.address = netns.fulcrum.address;
+
     services.spark-wallet = {
       address = netns.spark-wallet.address;
       extraArgs = "--no-tls";