Print out the goroutine id (#3433)

The TXT logger prints out the actual go routine ID

This feature depends on 'loggoroutine' build tag

```go build -tags loggoroutine```

formatter/logcat/logcat.go

@@ -0,0 +1,50 @@
+package logcat
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/sirupsen/logrus"
+
+	"github.com/netbirdio/netbird/formatter/levels"
+)
+
+// Formatter formats logs into text what is fit for logcat
+type Formatter struct {
+	levelDesc []string
+}
+
+// NewLogcatFormatter create new LogcatFormatter instance
+func NewLogcatFormatter() *Formatter {
+	return &Formatter{
+		levelDesc: levels.ValidLevelDesc,
+	}
+}
+
+// Format renders a single log entry
+func (f *Formatter) Format(entry *logrus.Entry) ([]byte, error) {
+	var fields string
+	keys := make([]string, 0, len(entry.Data))
+	for k, v := range entry.Data {
+		if k == "source" {
+			continue
+		}
+		keys = append(keys, fmt.Sprintf("%s: %v", k, v))
+	}
+
+	if len(keys) > 0 {
+		fields = fmt.Sprintf("[%s] ", strings.Join(keys, ", "))
+	}
+
+	level := f.parseLevel(entry.Level)
+
+	return []byte(fmt.Sprintf("[%s] %s%s %s\n", level, fields, entry.Data["source"], entry.Message)), nil
+}
+
+func (f *Formatter) parseLevel(level logrus.Level) string {
+	if len(f.levelDesc) < int(level) {
+		return ""
+	}
+
+	return f.levelDesc[level]
+}

formatter/logcat/logcat_test.go

@@ -0,0 +1,29 @@
+package logcat
+
+import (
+	"testing"
+	"time"
+
+	"github.com/sirupsen/logrus"
+)
+
+func TestLogcatMessageFormat(t *testing.T) {
+
+	someEntry := &logrus.Entry{
+		Data:    logrus.Fields{"att1": 1, "att2": 2, "source": "some/fancy/path.go:46"},
+		Time:    time.Date(2021, time.Month(2), 21, 1, 10, 30, 0, time.UTC),
+		Level:   3,
+		Message: "Some Message",
+	}
+
+	formatter := NewLogcatFormatter()
+	result, _ := formatter.Format(someEntry)
+
+	expectedString := "[WARN] [att1: 1, att2: 2] some/fancy/path.go:46 Some Message\n"
+	expectedStringVariant := "[WARN] [att2: 2, att1: 1] some/fancy/path.go:46 Some Message\n"
+	parsedString := string(result)
+	if parsedString != expectedString && parsedString != expectedStringVariant {
+		t.Errorf("The log messages don't match. Expected: '%s', got: '%s'", expectedString, parsedString)
+	}
+
+}