pianobar: add module to create config file (#7734)

Configuration entry similar to;

```nix
    programs.pianobar = {
      enable = true;
      user = "groovy-tunes@example.com";
      password_command = "cat /run/secrets/pianobar/groovy-tunes";
    };
```

... will produce a `~/.config/pianobar/config` file with content of;

```conf
user = groovy-tunes@example.com
password_command = cat /run/secrets/pianobar/groovy-tunes
```

...  and add `pianobar` to `home.packages` list.

All configurations that `man pianobar` documents _should_ available via
`extraOptions` attribute.

License, according to `NixOS/nixpkgs` is MIT, and that seems to match
what's shown on `PromyLOPh/pianobar` repo too;

- d92bfd5feb/pkgs/by-name/pi/pianobar/package.nix (L42o)
- https://github.com/PromyLOPh/pianobar/?tab=License-1-ov-file#readme

tests/modules/programs/pianobar/default.nix

@@ -0,0 +1,4 @@
+{
+  pianobar-minimally-required-configs = ./minimally-required-configs.nix;
+  pianobar-extra-settings = ./extra-settings.nix;
+}

tests/modules/programs/pianobar/extra-settings.conf

@@ -0,0 +1,29 @@
+act_help=h
+act_history=?
+at_icon=@
+audio_pipe=/path/to/fifo
+audio_quality=low
+autoselect={1,0}
+autostart_station=123456
+bind_to={if!tunX,host!127.0.0.1}
+buffer_seconds=5
+ca_bundle=/etc/ssl/certs/ca-certificates.crt
+control_proxy=http://user:password@host:port/
+event_command=/home/user/.config/pianobar/eventcmd
+fifo=/home/user/.config/pianobar/cmd
+format_list_song=%i) %a - %t%r
+format_msg_none=%s
+gain_mul=1.0
+history=5
+host=tuner.pandora.com
+love_icon=<3
+max_retry=3
+password_command=cat /run/secrets/pianobar/groovy-tunes
+proxy=http://user:password@host:port/
+sample_rate=0
+sort={name_az, name_za, quickmix_01_name_az, quickmix_01_name_za, quickmix_10_name_az, quickmix_10_name_za}
+timeout=30
+tired_icon=zZ
+tls_port=443
+user=groovy-tunes@example.com
+volume=30

tests/modules/programs/pianobar/extra-settings.nix

@@ -0,0 +1,42 @@
+{
+  programs.pianobar = {
+    enable = true;
+    settings = {
+      act_help = "h";
+      act_history = "?";
+      at_icon = "@";
+      audio_pipe = "/path/to/fifo";
+      audio_quality = "low";
+      autoselect = "{1,0}";
+      autostart_station = "123456";
+      bind_to = "{if!tunX,host!127.0.0.1}";
+      buffer_seconds = "5";
+      ca_bundle = "/etc/ssl/certs/ca-certificates.crt";
+      control_proxy = "http://user:password@host:port/";
+      event_command = "/home/user/.config/pianobar/eventcmd";
+      fifo = "/home/user/.config/pianobar/cmd";
+      format_list_song = "%i) %a - %t%r";
+      format_msg_none = "%s";
+      gain_mul = "1.0";
+      history = "5";
+      host = "tuner.pandora.com";
+      love_icon = "<3";
+      max_retry = "3";
+      password_command = "cat /run/secrets/pianobar/groovy-tunes";
+      proxy = "http://user:password@host:port/";
+      sample_rate = "0";
+      sort = "{name_az, name_za, quickmix_01_name_az, quickmix_01_name_za, quickmix_10_name_az, quickmix_10_name_za}";
+      timeout = "30";
+      tired_icon = "zZ";
+      tls_port = "443";
+      user = "groovy-tunes@example.com";
+      volume = "30";
+    };
+  };
+
+  nmt.script = ''
+    assertFileExists home-files/.config/pianobar/config
+    assertFileContent home-files/.config/pianobar/config \
+    ${./extra-settings.conf}
+  '';
+}

tests/modules/programs/pianobar/minimally-required-configs.conf

@@ -0,0 +1,2 @@
+password_command=cat /run/secrets/pianobar/groovy-tunes
+user=groovy-tunes@example.com

tests/modules/programs/pianobar/minimally-required-configs.nix

@@ -0,0 +1,15 @@
+{
+  programs.pianobar = {
+    enable = true;
+    settings = {
+      password_command = "cat /run/secrets/pianobar/groovy-tunes";
+      user = "groovy-tunes@example.com";
+    };
+  };
+
+  nmt.script = ''
+    assertFileExists home-files/.config/pianobar/config
+    assertFileContent home-files/.config/pianobar/config \
+    ${./minimally-required-configs.conf}
+  '';
+}