Add threaded session backend architecture with real SSH backend

src/session_backend.h

@@ -0,0 +1,57 @@
+#ifndef ORBITHUB_SESSION_BACKEND_H
+#define ORBITHUB_SESSION_BACKEND_H
+
+#include "profile_repository.h"
+
+#include <QObject>
+#include <QString>
+
+class SessionConnectOptions
+{
+public:
+    QString password;
+    QString privateKeyPath;
+    QString knownHostsPolicy;
+};
+
+enum class SessionState {
+    Disconnected,
+    Connecting,
+    Connected,
+    Failed,
+};
+
+class SessionBackend : public QObject
+{
+    Q_OBJECT
+
+public:
+    explicit SessionBackend(const Profile& profile, QObject* parent = nullptr)
+        : QObject(parent), m_profile(profile)
+    {
+    }
+    ~SessionBackend() override = default;
+
+    const Profile& profile() const
+    {
+        return m_profile;
+    }
+
+public slots:
+    virtual void connectSession(const SessionConnectOptions& options) = 0;
+    virtual void disconnectSession() = 0;
+    virtual void reconnectSession(const SessionConnectOptions& options) = 0;
+
+signals:
+    void stateChanged(SessionState state, const QString& message);
+    void eventLogged(const QString& message);
+    void connectionError(const QString& displayMessage, const QString& rawMessage);
+
+private:
+    Profile m_profile;
+};
+
+Q_DECLARE_METATYPE(SessionConnectOptions)
+Q_DECLARE_METATYPE(SessionState)
+
+#endif