[NOD-1223] Reorganize project (#868)

* [NOD-1223] Move all network stuff into a new network package.

* [NOD-1223] Delete the unused package testutil.

* [NOD-1223] Move infrastructure stuff into a new instrastructure package.

* [NOD-1223] Move domain stuff into a new domain package.

network/protocol/protocolerrors/protocolerrors.go

@@ -0,0 +1,52 @@
+package protocolerrors
+
+import "github.com/pkg/errors"
+
+// ProtocolError is an error that signifies a violation
+// of the peer-to-peer protocol
+type ProtocolError struct {
+	ShouldBan bool
+	Cause     error
+}
+
+func (e *ProtocolError) Error() string {
+	return e.Cause.Error()
+}
+
+func (e *ProtocolError) Unwrap() error {
+	return e.Cause
+}
+
+// Errorf formats according to a format specifier and returns the string
+// as a ProtocolError.
+func Errorf(shouldBan bool, format string, args ...interface{}) error {
+	return &ProtocolError{
+		ShouldBan: shouldBan,
+		Cause:     errors.Errorf(format, args...),
+	}
+}
+
+// New returns a ProtocolError with the supplied message.
+// New also records the stack trace at the point it was called.
+func New(shouldBan bool, message string) error {
+	return &ProtocolError{
+		ShouldBan: shouldBan,
+		Cause:     errors.New(message),
+	}
+}
+
+// Wrap wraps the given error and returns it as a ProtocolError.
+func Wrap(shouldBan bool, err error, message string) error {
+	return &ProtocolError{
+		ShouldBan: shouldBan,
+		Cause:     errors.Wrap(err, message),
+	}
+}
+
+// Wrapf wraps the given error with the given format and returns it as a ProtocolError.
+func Wrapf(shouldBan bool, err error, format string, args ...interface{}) error {
+	return &ProtocolError{
+		ShouldBan: shouldBan,
+		Cause:     errors.Wrapf(err, format, args...),
+	}
+}