feat: add unit functions to dashboard (#890)

dashboard.json updated to have tick_config that contains list 
of column names and their unit names

sample json -
`
{
    "version": "v1",
    "name": "helloa",
    "description": "ahdkadkadvnasdsa",
    "dashboard_id": "admin.1724033591071",
    "user_id": "admin",
    "time_filter": null,
    "refresh_interval": 60,
    "tiles": [
        {
            "name": "final",
            "tile_id": "admin.1724033591071255",
            "description": "sdsds",
            "query": "select * from teststream LIMIT 100",
            "order": 2,
            "visualization": {
                "visualization_type": "donut-chart",
                "circular_chart_config": {
                    "name_key": "app_meta",
                    "value_key": "device_id"
                },
                "graph_config": null,
                "size": "sm",
                "color_config": [],
                "tick_config": [{"key": "device_id", "unit": "unit_name"}]
            }
        }
    ]
}
`

Author: nikhilsinhaparseable

server/src/users/dashboards.rs

@@ -45,6 +45,7 @@ pub struct Visualization {
     graph_config: Option<GraphConfig>,
     size: String,
     color_config: Vec<ColorConfig>,
+    tick_config: Vec<TickConfig>,
 }
 
 #[derive(Debug, Serialize, Deserialize, Default, Clone)]
@@ -65,6 +66,12 @@ pub struct ColorConfig {
     color_palette: String,
 }
 
+#[derive(Debug, Serialize, Deserialize, Default, Clone)]
+pub struct TickConfig {
+    key: String,
+    unit: String,
+}
+
 #[derive(Debug, Serialize, Deserialize, Default, Clone)]
 pub struct Dashboard {
     pub version: Option<String>,