cli: error classification refactoring (#386)

* make errorx classifier less dependent on strings

* adapt errorx tests

* added syserror comment

* localized classification of quic errors

* localized classification of resolver errors

* (fix) move "no such host" error to global classifier

* moved x509 errors to local TLS error classifier

* added qtls error classification for quicdialer

* add Classifier to SafeErrWrapperBuilder

* windows/unix specific files for errno constants

* added errno ETIMEDOUT, tests

* added TLS alert constants

* added FailureSSLHandshake test, improved switch style

* added more network based system error constants for future use

* (fix) import style

* (fix) errorx typos/style

* (fix) robustness of SafeErrWrapperBuilder, added comments

* (fix) reversed unnecessary changes, added comments

* (fix) style and updated comment

* errorx: added future re-structuring comment

* (fix) typo TLS alert code 51

* added comment

* alert mapping: added comment

* Update errorx.go

* Update internal/engine/netx/errorx/errorx.go

Co-authored-by: Simone Basso <bassosimone@gmail.com>

internal/engine/netx/quicdialer/errorwrapper.go

@@ -23,9 +23,10 @@ func (d ErrorWrapperDialer) DialContext(
 	err = errorx.SafeErrWrapperBuilder{
 		// ConnID does not make any sense if we've failed and the error
 		// does not make any sense (and is nil) if we succeeded.
-		DialID:    dialID,
-		Error:     err,
-		Operation: errorx.QUICHandshakeOperation,
+		Classifier: errorx.ClassifyQUICFailure,
+		DialID:     dialID,
+		Error:      err,
+		Operation:  errorx.QUICHandshakeOperation,
 	}.MaybeBuild()
 	if err != nil {
 		return nil, err