Add authentication dialog

Introduce start_auth_flow, a function invoked by typing `/auth username`
in OOC. It sends an public-key authentication request to the server,
starting the entire flow.

The flow invoves two dialogs: to select the key, and to enter the
passphrase to unlock the key. For convenience, each successful unlock
also remembers the key for that username on the server, storing this
in `saved_auth.json` (I chose JSON because I wanted it to stay
human-editable; INI would be better, but it suffers from bad platform
quirks in Qt).

1 files changed, 3 insertions, 0 deletions

diff --git a/src/serverdata.h b/src/serverdata.h
index 9935185..4f4e572 100644
--- a/src/serverdata.h
+++ b/src/serverdata.h
@@ -134,6 +134,9 @@ public:
    */
   void set_asset_url(const QString &f_asset_url);
 
+  // There's no need for accessors here.
+  QString m_server_hostname;
+
 private:
   /// The features available on the server. Determines what
   QStringList m_features;