network enhanecment / refactor (#361)

* chore(network): improve connectivity check

* refactor(network): rewrite network and timesync component

* feat(display): show cloud connection status

* chore: change logging verbosity

* chore(websecure): update log message

* fix(ota): validate root certificate when downloading update

* feat(ui): add network settings tab

* fix(display): cloud connecting animation

* fix: golintci issues

* feat: add network settings tab

* feat(timesync): query servers in parallel

* refactor(network): move to internal/network package

* feat(timesync): add metrics

* refactor(log): move log to internal/logging package

* refactor(mdms): move mdns to internal/mdns package

* feat(developer): add pprof endpoint

* feat(logging): add a simple logging streaming endpoint

* fix(mdns): do not start mdns until network is up

* feat(network): allow users to update network settings from ui

* fix(network): handle errors when net.IPAddr is nil

* fix(mdns): scopedLogger SIGSEGV

* fix(dhcp): watch directory instead of file to catch fsnotify.Create event

* refactor(nbd): move platform-specific code to different files

* refactor(native): move platform-specific code to different files

* chore: fix linter issues

* chore(dev_deploy): allow to override PION_LOG_TRACE

internal/logging/utils.go

@@ -0,0 +1,32 @@
+package logging
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/rs/zerolog"
+)
+
+var defaultLogger = zerolog.New(os.Stdout).Level(zerolog.InfoLevel)
+
+func GetDefaultLogger() *zerolog.Logger {
+	return &defaultLogger
+}
+
+func ErrorfL(l *zerolog.Logger, format string, err error, args ...interface{}) error {
+	// TODO: move rootLogger to logging package
+	if l == nil {
+		l = &defaultLogger
+	}
+
+	l.Error().Err(err).Msgf(format, args...)
+
+	if err == nil {
+		return fmt.Errorf(format, args...)
+	}
+
+	err_msg := err.Error() + ": %v"
+	err_args := append(args, err)
+
+	return fmt.Errorf(err_msg, err_args...)
+}