feat: enable filtering console output by severity level

pkg/level/level.go

@@ -1,6 +1,8 @@
 package level
 
 import (
+	"strings"
+
 	"git.ma-al.com/maal-libraries/observer/pkg/syslog"
 	"go.opentelemetry.io/otel/attribute"
 )
@@ -61,20 +63,21 @@ func (l SeverityLevel) String() string {
 }
 
 func FromString(level string) SeverityLevel {
+	level = strings.ToLower(level)
 	switch level {
-	case "ALERT":
+	case "alert":
 		return ALERT
-	case "CRIT":
+	case "crit", "critical":
 		return CRIT
-	case "ERR":
+	case "err", "error":
 		return ERR
-	case "WARN":
+	case "warn", "warning":
 		return WARN
-	case "INFO":
+	case "info":
 		return INFO
-	case "DEBUG":
+	case "debug":
 		return DEBUG
-	case "TRACE":
+	case "trace":
 		return TRACE
 	default:
 		return unset