treewide: remove unit descriptions

Systemd's `Description` option is a misnomer (as confessed by `man systemd.unit`):
Its value is used by user-facing tools in place of the unit file name, so this option
could have been more aptly named `label` or `name`.
`Description` should only be set if the unit file name is not sufficient for naming a unit.
This is not the case for our services, except for `systemd.services.nb-netns-bridge`
whose description has been kept.

As an example how this affects users, weird journal lines like
```
nb-test systemd[1]: Starting Run clightningd...
```
are now replaced by
```
nb-test systemd[1]: Starting clightning.service...
```

modules/bitcoind.nix

@@ -312,7 +312,6 @@ in {
     ];
 
     systemd.services.bitcoind = {
-      description = "Bitcoin daemon";
       requires = [ "nix-bitcoin-secrets.target" ];
       after = [ "network.target" "nix-bitcoin-secrets.target" ];
       wantedBy = [ "multi-user.target" ];

modules/btcpayserver.nix

@@ -123,7 +123,6 @@ in {
         port=${toString cfg.nbxplorer.port}
       '';
     in {
-      description = "Run nbxplorer";
       wantedBy = [ "multi-user.target" ];
       requires = [ "bitcoind.service" ];
       after = [ "bitcoind.service" ];

modules/clightning.nix

@@ -118,7 +118,6 @@ in {
     ];
 
     systemd.services.clightning = {
-      description = "Run clightningd";
       path  = [ nbPkgs.bitcoind ];
       wantedBy = [ "multi-user.target" ];
       requires = [ "bitcoind.service" ];

modules/electrs.nix

@@ -68,7 +68,6 @@ in {
     ];
 
     systemd.services.electrs = {
-      description = "Electrs Electrum Server";
       wantedBy = [ "multi-user.target" ];
       requires = [ "bitcoind.service" ];
       after = [ "bitcoind.service" ];

modules/joinmarket.nix

@@ -171,7 +171,6 @@ in {
     };
 
     systemd.services.joinmarket = {
-      description = "JoinMarket Daemon";
       wantedBy = [ "multi-user.target" ];
       requires = [ "bitcoind.service" ];
       after = [ "bitcoind.service" ];
@@ -226,7 +225,6 @@ in {
           chmod +x $out
         '';
     in {
-      description = "CoinJoin maker bot to gain privacy and passively generate income";
       wantedBy = [ "joinmarket.service" ];
       requires = [ "joinmarket.service" ];
       after = [ "joinmarket.service" ];

modules/liquid.nix

@@ -220,7 +220,6 @@ in {
     ];
 
     systemd.services.liquidd = {
-      description = "Elements daemon providing access to the Liquid sidechain";
       requires = [ "bitcoind.service" ];
       after = [ "bitcoind.service" ];
       wantedBy = [ "multi-user.target" ];

modules/lnd.nix

@@ -173,7 +173,6 @@ in {
     };
 
     systemd.services.lnd = {
-      description = "Run LND";
       wantedBy = [ "multi-user.target" ];
       requires = [ "bitcoind.service" ];
       after = [ "bitcoind.service" ];

modules/recurring-donations.nix

@@ -88,7 +88,6 @@ in {
     users.groups.recurring-donations = {};
 
     systemd.services.recurring-donations = {
-      description = "Run recurring-donations";
       requires = [ "clightning.service" ];
       after = [ "clightning.service" ];
       path = with pkgs; [ nix-bitcoin.clightning curl sudo jq ];

modules/spark-wallet.nix

@@ -67,7 +67,6 @@ in {
     users.groups.spark-wallet = {};
 
     systemd.services.spark-wallet = {
-      description = "Run spark-wallet";
       wantedBy = [ "multi-user.target" ];
       requires = [ "clightning.service" ];
       after = [ "clightning.service" ];