main: cleanup unused struct fields

examples/example_dashboards.yaml

@@ -68,8 +68,6 @@
   logs:
     - title: Systemd Service Logs
       query_type: Range
-      yaxes:
-        - anchor: "y" # This axis is y
       source: http://heimdall:3100
       query: |
         {job="systemd-journal"}

src/dashboard.rs

@@ -131,9 +131,7 @@ pub struct Graph {
 #[derive(Deserialize)]
 pub struct LogStream {
     pub title: String,
-    pub legend_orientation: Option<Orientation>,
     pub source: String,
-    pub yaxes: Vec<AxisDefinition>,
     pub query: String,
     pub span: Option<GraphSpan>,
     pub limit: Option<usize>,