feat: add --ids-only flag to --list mode for scripting

Outputs one ID per line with no header. Errors if used with any mode
other than --list. Works with both local and client (remote) list.

src/config.rs

@@ -191,6 +191,8 @@ pub struct Settings {
     pub table_config: TableConfig,
     #[serde(default)]
     pub human_readable: bool,
+    #[serde(default)]
+    pub ids_only: bool,
     pub output_format: Option<String>,
     #[serde(default)]
     pub quiet: bool,
@@ -277,6 +279,10 @@ impl Settings {
             config_builder = config_builder.set_override("human_readable", true)?;
         }
 
+        if args.options.ids_only {
+            config_builder = config_builder.set_override("ids_only", true)?;
+        }
+
         if let Some(output_format) = &args.options.output_format {
             config_builder =
                 config_builder.set_override("output_format", output_format.as_str())?;