Comm session re-architecture and self comm channel. (#145)

* Introduced self comm channel instead of loopback websocket.
* Introduced comm_session and comm_server inheritance hierarchy.
* Separated peer session and user session classes.

src/usr/user_comm_session.cpp

@@ -0,0 +1,41 @@
+#include "../pchheader.hpp"
+#include "../util.hpp"
+#include "user_comm_session.hpp"
+#include "user_session_handler.hpp"
+
+namespace usr
+{
+    void user_comm_session::handle_connect()
+    {
+        usr::handle_user_connect(*this);
+    }
+
+    int user_comm_session::handle_message(std::string_view msg)
+    {
+        return usr::handle_user_message(*this, msg);
+    }
+
+    void user_comm_session::handle_close()
+    {
+        usr::handle_user_close(*this);
+    }
+
+    /**
+     * Returns printable name for the session based on uniqueid (used for logging).
+     */
+    const std::string user_comm_session::display_name()
+    {
+        if (challenge_status == comm::CHALLENGE_STATUS::CHALLENGE_VERIFIED)
+        {
+            // User sessions use binary pubkey as unique id. So we need to convert to hex.
+            std::string hex;
+            util::bin2hex(hex,
+                          reinterpret_cast<const unsigned char *>(uniqueid.data()),
+                          uniqueid.length());
+            return hex.substr(2, 10) + (is_inbound ? ":in" : ":out"); // Skipping first 2 bytes key type prefix.
+        }
+
+        return comm_session::display_name();
+    }
+
+} // namespace usr