WIP settings system.

- updated dbdiagrams schema
- [BREAKING] force failure if `notify.filter_attributes` or `notify.level` is set
- added Settings table (and default values during migration)
- Added Save Settings and Get Settings functions.
- Added web API endpoints for getting and saving settings.
- Deprecated old Notify* constants. Created new MetricsStatus* and MetricsNotifyLevel constants.

webapp/backend/pkg/web/handler/get_settings.go

@@ -0,0 +1,25 @@
+package handler
+
+import (
+	"github.com/analogj/scrutiny/webapp/backend/pkg/database"
+	"github.com/gin-gonic/gin"
+	"github.com/sirupsen/logrus"
+	"net/http"
+)
+
+func GetSettings(c *gin.Context) {
+	logger := c.MustGet("LOGGER").(logrus.FieldLogger)
+	deviceRepo := c.MustGet("DEVICE_REPOSITORY").(database.DeviceRepo)
+
+	settings, err := deviceRepo.GetSettings(c)
+	if err != nil {
+		logger.Errorln("An error occurred while retrieving settings", err)
+		c.JSON(http.StatusInternalServerError, gin.H{"success": false})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{
+		"success":  true,
+		"settings": settings,
+	})
+}