TST: Add test csv and cfood for new unit tests

unittests/test_directories/examples_tables/ExperimentalData/test_with_empty.csv

+event,date
+event_a,2025-02-06
+event_b,
+event_c,2025-02-06T09:00:00

unittests/test_directories/examples_tables/crawler_for_issue_112.yml

+ExperimentalData:
+  type: Directory
+  match: ExperimentalData
+  subtree:
+    CSVTable:
+      type: CSVTableConverter
+      match: "test_with_empty\\.csv"
+      subtree:
+        Row:
+          type: DictElement
+          records:
+            Event:
+          subtree:
+            EventName:
+              type: TextElement
+              match_name: "event"
+              match_value: "(?P<name>.*)"
+              records:
+                Event:
+                  name: $name
+            Date:
+              type: Datetime
+              match_name: "date"
+              match_value: "(?P<date>.+)"
+              records:
+                Event:
+                  event_time: $date