Implemented initial DLPak design

Implemented DLPak design with zip storage, DLPak consists of two files,
a manifest.json which provides details on the signals, time of recording
and currently blank comment field and data.csv which stores all the
signals as csv with the nanosecond timestamp and indexed against the
signal id

src/dynalab_core/errors.py

@@ -9,3 +9,12 @@ class CoreError(Exception):
 
 class CoreStateMismatchError(CoreError):
     """DynaLab Core state error."""
+
+
+# DLPak error declarations
+class DLPakError(Exception):
+    """DLPak error."""
+
+
+class DLPakNoDataError(DLPakError):
+    """DLPak no data error."""