data: indexer processes

* TaskBuildIndex starts seperate indexer processes and communicates via shared memory
* indexer processes get restarted if they fail
* indexer processes are killed when the app closes or crashes
* added utility class SharedMemory to allocate and access shared memory, providing basic data structures
* added SharedMemoryGarbageCollector for keeping track of running instances and cleaning up shared memory in case of a crash
* show errors for source files that crashed during indexing
* added basic exception handling to task scheduling
* added option to turn off processes and use threads in preferences, but still use shared memory

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src/lib_gui/platform_includes/includesMac.h

@@ -8,6 +8,7 @@
 
 #include "qt/utility/utilityQt.h"
 #include "utility/AppPath.h"
+#include "utility/file/FilePath.h"
 #include "utility/ResourcePaths.h"
 #include "utility/UserPaths.h"
 
@@ -91,7 +92,7 @@ void setupApp(int argc, char *argv[])
 
 	if (!appIsMacBundle)
 	{
-		UserPaths::setUserDataPath(FilePath(path.absolute().str() + "/user/"));
+		UserPaths::setUserDataPath(FilePath("./user/"));
 	}
 	else
 	{