Sqlite: Add session support

Session are captured by hooking in the sqlite changes. They are saved in
blobs and containing inserts, update and deletes. Because the are
semantically coupled to translactions we add a

Change-Id: Ie095558ebc50601fcaae32958ebeeb98b72d73b9
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

src/libs/sqlite/sqliteexception.h

@@ -43,7 +43,7 @@ public:
         , m_sqliteErrorMessage(std::move(sqliteErrorMessage))
     {}
 
-    const char *what() const noexcept override { return m_sqliteErrorMessage.data(); }
+    const char *what() const noexcept override { return m_whatErrorHasHappen; }
 
     void printWarning() const;
 
@@ -283,4 +283,20 @@ public:
     {}
 };
 
+class CannotApplyChangeSet : public Exception
+{
+public:
+    CannotApplyChangeSet(const char *whatErrorHasHappen)
+        : Exception(whatErrorHasHappen)
+    {}
+};
+
+class ChangeSetIsMisused : public Exception
+{
+public:
+    ChangeSetIsMisused(const char *whatErrorHasHappen)
+        : Exception(whatErrorHasHappen)
+    {}
+};
+
 } // namespace Sqlite