Move test runs into the test-run folder, add TimestampStrings, add basic tests via pytest

pytest added for dev.
Move all the test run python scripts into the "test-run" folder, so we can use the tests/ folder for just tests.

Setup one test for the TimestampStrings class with pytests in tests/unit/string_handling/test_timestamp_strings.py

src/corelibs/string_handling/timestamp_strings.py

@@ -0,0 +1,26 @@
+"""
+Current timestamp strings and time zones
+"""
+
+from datetime import datetime
+from zoneinfo import ZoneInfo, ZoneInfoNotFoundError
+
+
+class TimestampStrings:
+    """
+    set default time stamps
+    """
+
+    time_zone: str = 'Asia/Tokyo'
+
+    def __init__(self, time_zone: str | None = None):
+        self.timestamp_now = datetime.now()
+        self.time_zone = time_zone if time_zone is not None else __class__.time_zone
+        try:
+            self.timestamp_now_tz = datetime.now(ZoneInfo(self.time_zone))
+        except ZoneInfoNotFoundError as e:
+            raise ValueError(f'Zone could not be loaded [{self.time_zone}]: {e}') from e
+        self.today = self.timestamp_now.strftime('%Y-%m-%d')
+        self.timestamp = self.timestamp_now.strftime("%Y-%m-%d %H:%M:%S")
+        self.timestamp_tz = self.timestamp_now_tz.strftime("%Y-%m-%d %H:%M:%S %Z")
+        self.timestamp_file = self.timestamp_now.strftime("%Y-%m-%d_%H%M%S")