on settings save, return the new settings.

update the frontend to persist settings to the database.
Using ScrutinyConfigService instead of TreoConfigService.
Using snake case settings in frontend.
Make sure we're using AppConfig type where possible.

webapp/frontend/src/app/modules/dashboard/dashboard.component.ts

@@ -14,7 +14,7 @@ import {DashboardService} from 'app/modules/dashboard/dashboard.service';
 import {MatDialog} from '@angular/material/dialog';
 import {DashboardSettingsComponent} from 'app/layout/common/dashboard-settings/dashboard-settings.component';
 import {AppConfig} from 'app/core/config/app.config';
-import {TreoConfigService} from '@treo/services/config';
+import {ScrutinyConfigService} from 'app/core/config/scrutiny-config.service';
 import {Router} from '@angular/router';
 import {TemperaturePipe} from 'app/shared/temperature.pipe';
 import {DeviceTitlePipe} from 'app/shared/device-title.pipe';
@@ -43,13 +43,13 @@ export class DashboardComponent implements OnInit, AfterViewInit, OnDestroy
      * Constructor
      *
      * @param {DashboardService} _dashboardService
-     * @param {TreoConfigService} _configService
+     * @param {ScrutinyConfigService} _configService
      * @param {MatDialog} dialog
      * @param {Router} router
      */
     constructor(
         private _dashboardService: DashboardService,
-        private _configService: TreoConfigService,
+        private _configService: ScrutinyConfigService,
         public dialog: MatDialog,
         private router: Router,
     )
@@ -150,7 +150,7 @@ export class DashboardComponent implements OnInit, AfterViewInit, OnDestroy
                 continue
             }
 
-            const deviceName = DeviceTitlePipe.deviceTitleWithFallback(deviceSummary.device, this.config.dashboardDisplay)
+            const deviceName = DeviceTitlePipe.deviceTitleWithFallback(deviceSummary.device, this.config.dashboard_display)
 
             const deviceSeriesMetadata = {
                 name: deviceName,
@@ -161,7 +161,7 @@ export class DashboardComponent implements OnInit, AfterViewInit, OnDestroy
                 const newDate = new Date(tempHistory.date);
                 deviceSeriesMetadata.data.push({
                     x: newDate,
-                    y: TemperaturePipe.formatTemperature(tempHistory.temp, this.config.temperatureUnit, false)
+                    y: TemperaturePipe.formatTemperature(tempHistory.temp, this.config.temperature_unit, false)
                 })
             }
             deviceTemperatureSeries.push(deviceSeriesMetadata)
@@ -212,7 +212,7 @@ export class DashboardComponent implements OnInit, AfterViewInit, OnDestroy
                 y    : {
 
                     formatter: (value) => {
-                        return TemperaturePipe.formatTemperature(value, this.config.temperatureUnit, true) as string;
+                        return TemperaturePipe.formatTemperature(value, this.config.temperature_unit, true) as string;
                     }
                 }
             },