standardize commonly used attributes

Some commonly used at maal attributes have been encoded as consts with
convinience wrappers similar to those of semconv package from otel sdk.
Additionally some utils that can generate mutliple attributes were added.

pkg/tracer/event.go

@@ -1,29 +1,11 @@
 package tracer
 
 import (
-	"encoding/json"
-
 	"git.ma-al.com/gora_filip/observer/pkg/level"
-	"go.opentelemetry.io/otel/attribute"
 	"go.opentelemetry.io/otel/codes"
 	"go.opentelemetry.io/otel/trace"
 )
 
-func LongMessage(message string) attribute.KeyValue {
-	return attribute.KeyValue{Key: "long_message_", Value: attribute.StringValue(message)}
-}
-
-func Level(level level.SyslogLevel) attribute.KeyValue {
-	return attribute.KeyValue{Key: "level_", Value: attribute.Int64Value(int64(level))}
-}
-
-func JsonAttr(key string, jsonEl map[string]interface{}) attribute.KeyValue {
-
-	jsonStr, _ := json.Marshal(jsonEl)
-	return attribute.KeyValue{Key: attribute.Key(key), Value: attribute.StringValue(string(jsonStr))}
-
-}
-
 func RecordError(span trace.Span, err error) error {
 	span.SetStatus(codes.Error, err.Error())
 	span.RecordError(err)