logic: reimplemented task system to abort ast visiting

* reimplemented interrupting TaskParseCxx by adding a listener for the MessageInterruptTask and returning a failure status code on update. This cancels the parent sequence task which results in the indexed items not getting inserted into the persistent storage
* removed the capability for interrupting from TaskScheduler
* changed task system to be closer to the standard behavior tree implementation
* changed task system to accommodate the 3 status return types: Running, Success and Failure
* made TaskGroupSequential fail once a member task fails
* made TaskGroupParallel fail once a member task fails
* split TaskParse... into one task for indexing and one task for injecting
* added TaskRunner that handles updating and resetting the managed task
* fixed numbers that are shown as parsed file count in indexing ui
* fixed deadlock that originated from interaction between TaskScheduler and MessageQueue (one thread wanted to destroy a message listener on a task while the other one wanted to send as message as a task)

src/lib/data/TaskInjectStorage.cpp

@@ -0,0 +1,30 @@
+#include "data/TaskInjectStorage.h"
+
+#include "data/Storage.h"
+
+TaskInjectStorage::TaskInjectStorage(
+	std::shared_ptr<Storage> source,
+	std::shared_ptr<Storage> target
+)
+	: m_source(source)
+	, m_target(target)
+{
+}
+
+void TaskInjectStorage::doEnter()
+{
+}
+
+Task::TaskState TaskInjectStorage::doUpdate()
+{
+	m_target->inject(m_source.get());
+	return STATE_SUCCESS;
+}
+
+void TaskInjectStorage::doExit()
+{
+}
+
+void TaskInjectStorage::doReset()
+{
+}