chore: remove deprecated sync_excempt target and switch export_stats to dr.stats

- Delete the sync_excempt Makefile target that was stubbed with a timeout warning
- Change export_stats to call dr.stats instead of dr.stats_all
- Remove extraneous blank lines in Makefile for cleaner formatting

Makefile

@@ -8,8 +8,6 @@ build:
 	./venv/bin/python -m build .
 	./venv/bin/python -m pip install -e .
 
-
-
 sync:
 	./venv/bin/dr.sync
 
@@ -17,13 +15,10 @@ clean:
 	-@rm -r export
 	mkdir -p export 
 
-sync_excempt:
-	@echo "Sync is not executed because it's a lengthy process ending with timeout error."
-
 export_stats:
 	@echo "Make sure you have ran 'make sync' first. Results will be in ./export/"
 	@echo "Exporting statisticts."
-	./venv/bin/dr.stats_all
+	./venv/bin/dr.stats
 
 export_dataset:
 	@echo "Make sure you have ran 'make sync' first."