ringaccount: save registered name in configuration

Use the account configuration to store the registered name,
allowing to know the account registered name for disabled accounts,
before account registration happens,
or if the name server is not reachable and the name cache
was cleared.

This allows to show the account registered name instead of
the RingID more consistently in clients. The field is not
authoritative as information from the name server always
take precedence.

Change-Id: Ief8725da57d609ce9bbaeda6b2d564638ea3b191

src/ringdht/ringaccount.cpp

@@ -716,6 +716,8 @@ void RingAccount::serialize(YAML::Emitter &out)
     out << YAML::Key << Conf::RING_ACCOUNT_RECEIPT << YAML::Value << receipt_;
     out << YAML::Key << Conf::RING_ACCOUNT_RECEIPT_SIG << YAML::Value << YAML::Binary(receiptSignature_.data(), receiptSignature_.size());
     out << YAML::Key << DRing::Account::ConfProperties::RING_DEVICE_NAME << YAML::Value << ringDeviceName_;
+    if (not registeredName_.empty())
+        out << YAML::Key << DRing::Account::VolatileProperties::REGISTERED_NAME << YAML::Value << registeredName_;
 
     // tls submap
     out << YAML::Key << Conf::TLS_KEY << YAML::Value << YAML::BeginMap;
@@ -747,6 +749,13 @@ void RingAccount::unserialize(const YAML::Node &node)
     } catch (const std::exception& e) {
         RING_WARN("can't read device name: %s", e.what());
     }
+    if (registeredName_.empty()) {
+        try {
+            parseValue(node, DRing::Account::VolatileProperties::REGISTERED_NAME, registeredName_);
+        } catch (const std::exception& e) {
+            RING_WARN("can't read device name: %s", e.what());
+        }
+    }
 
     try {
         parsePath(node, DRing::Account::ConfProperties::ARCHIVE_PATH, archivePath_, idPath_);