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/tlsdialer/tls.go

@@ -71,9 +71,10 @@ func (h ErrorWrapperTLSHandshaker) Handshake(
 	connID := connid.Compute(conn.RemoteAddr().Network(), conn.RemoteAddr().String())
 	tlsconn, state, err := h.TLSHandshaker.Handshake(ctx, conn, config)
 	err = errorx.SafeErrWrapperBuilder{
-		ConnID:    connID,
-		Error:     err,
-		Operation: errorx.TLSHandshakeOperation,
+		Classifier: errorx.ClassifyTLSFailure,
+		ConnID:     connID,
+		Error:      err,
+		Operation:  errorx.TLSHandshakeOperation,
 	}.MaybeBuild()
 	return tlsconn, state, err
 }