treewide: use bool literals for systemd

Run this from the repo root to check that there are no more remaining
bool strings:
grep -P '"true"|"false"' -r --exclude-dir=.git

modules/btcpayserver.nix

@@ -193,7 +193,7 @@ in {
         Restart = "on-failure";
         RestartSec = "10s";
         ReadWritePaths = [ cfg.nbxplorer.dataDir ];
-        MemoryDenyWriteExecute = "false";
+        MemoryDenyWriteExecute = false;
       } // nbLib.allowedIPAddresses cfg.nbxplorer.tor.enforce;
     };
 
@@ -239,7 +239,7 @@ in {
         Restart = "on-failure";
         RestartSec = "10s";
         ReadWritePaths = [ cfg.btcpayserver.dataDir ];
-        MemoryDenyWriteExecute = "false";
+        MemoryDenyWriteExecute = false;
       } // nbLib.allowedIPAddresses cfg.btcpayserver.tor.enforce;
     }; in self;
 

modules/onion-addresses.nix

@@ -55,8 +55,8 @@ in {
         RemainAfterExit = true;
         StateDirectory = "onion-addresses";
         StateDirectoryMode = "771";
-        PrivateNetwork = "true"; # This service needs no network access
-        PrivateUsers = "false";
+        PrivateNetwork = true; # This service needs no network access
+        PrivateUsers = false;
         CapabilityBoundingSet = "CAP_CHOWN CAP_FSETID CAP_SETFCAP CAP_DAC_OVERRIDE CAP_DAC_READ_SEARCH CAP_FOWNER CAP_IPC_OWNER";
       };
       script = ''