Merge fort-nix/nix-bitcoin#425: Misc. improvements

def64a73b8 treewide: use TODO-EXTERNAL (Erik Arvstedt)
6f37bef2a3 netns-isolation: simplify firewall setup (Erik Arvstedt)
f52059ce3c docs: add doc 'Configuration and maintenance' (Erik Arvstedt)
94aee8174d usage.md: add section `Managing services` (Erik Arvstedt)
8cc7b83da1 usage.md: convert to '#' heading syntax (Erik Arvstedt)
91fbcfcc77 faq.md: reformat (Erik Arvstedt)
9e4f4d6b0f bitcoind: add option `txindex` (Erik Arvstedt)
10a744a598 rtl: add option `extraCurrency` (Erik Arvstedt)
62a2602e78 electrs: use dataDir for storing extra config (Erik Arvstedt)
9bda7305fd services: add `tor.*` options (Erik Arvstedt)
ff24e73ad7 onion-addresses: fix files not being copied (Erik Arvstedt)
c6fe017aeb netns-isolation: avoid creating service files for disabled services (Erik Arvstedt)
017e08ca10 btcpayserver: move nbxplorer options to bottom (Erik Arvstedt)
e1d869d76c modules.nix: move rtl to fix topological sorting (Erik Arvstedt)
e44cd7ecdc rtl: improve descriptions (Erik Arvstedt)
bd275d3a9a minor improvements (Erik Arvstedt)
8aa28da110 remove `recurring-donations` module (Erik Arvstedt)

Pull request description:

ACKs for top commit:
  nixbitcoin:
    ACK def64a73b8
  jonasnick:
    ACK def64a73b8

Tree-SHA512: 13acd2a3dd73c07f9c31874c8e961f12f39accb48847cbad08479b9a8154b79a6f186819272072dfb5c4768264b81f6e058e9afa57a729db2096784e48352dfd

modules/electrs.nix

@@ -12,7 +12,7 @@ let
     port = mkOption {
       type = types.port;
       default = 50001;
-      description = "RPC port.";
+      description = "Port to listen for RPC connections.";
     };
     dataDir = mkOption {
       type = types.path;
@@ -39,7 +39,7 @@ let
       default = cfg.user;
       description = "The group as which to run electrs.";
     };
-    enforceTor = nbLib.enforceTor;
+    tor.enforce = nbLib.tor.enforce;
   };
 
   cfg = config.services.electrs;
@@ -74,10 +74,8 @@ in {
           > electrs.toml
         '';
       serviceConfig = nbLib.defaultHardening // {
-        RuntimeDirectory = "electrs";
-        RuntimeDirectoryMode = "700";
         # electrs only uses the working directory for reading electrs.toml
-        WorkingDirectory = "/run/electrs";
+        WorkingDirectory = cfg.dataDir;
         ExecStart = ''
           ${config.nix-bitcoin.pkgs.electrs}/bin/electrs \
           --log-filters=INFO \
@@ -95,7 +93,7 @@ in {
         Restart = "on-failure";
         RestartSec = "10s";
         ReadWritePaths = cfg.dataDir;
-      } // nbLib.allowedIPAddresses cfg.enforceTor;
+      } // nbLib.allowedIPAddresses cfg.tor.enforce;
     };
 
     users.users.${cfg.user} = {