feat(shared): create time functions

shared/libretime_shared/datetime.py

@@ -0,0 +1,14 @@
+from datetime import time
+
+
+def time_in_seconds(value: time) -> float:
+    return (
+        value.hour * 60 * 60
+        + value.minute * 60
+        + value.second
+        + value.microsecond / 1000000.0
+    )
+
+
+def time_in_milliseconds(value: time) -> float:
+    return time_in_seconds(value) * 1000