Add GetUptimeByKey to store interface

storage/store/common/errors.go

@@ -0,0 +1,8 @@
+package common
+
+import "errors"
+
+var (
+	ErrServiceNotFound  = errors.New("service not found")                // When a service does not exist in the store
+	ErrInvalidTimeRange = errors.New("'from' cannot be older than 'to'") // When an invalid time range is provided
+)