Added ValueBuffer implementation and simple recording

ValueBuffer is now the default buffer object for storing data for
recording and processing purposes, a simple recording implementation has
been done, core.py example starts recording as soon as the core has
started then on exit it saves the output as a csv file through the
ValueBuffer export_csv method

test/manual/core.py

@@ -19,6 +19,7 @@ config = CoreConfig(port=8765)
 log.info("Configured manual core on %s", config.bind_str())
 dl_core = Core(config)
 dl_core.start()
+dl_core.start_recording()
 
 try:
     while True:
@@ -27,4 +28,5 @@ try:
         log.debug(f"Core values: {values}")
 except KeyboardInterrupt:
     log.info("Received keyboard interrupt")
+    dl_core.stop_recording()
     dl_core.stop()

test/manual/peer.py

@@ -116,24 +116,12 @@ def value_sender_thread(
 
                 next_send_time += period
 
-            value = ValueDescriptor(
-                signal_id=signal_id, value=2.0, timestamp=monotonic_ns()
-            )
-
-            message = ValueBatch(
-                values=[
-                    value,
-                    value,
-                    value,
-                    value,
-                    value,
-                    value,
-                    value,
-                    value,
-                    value,
-                    value,
-                ]
-            )
+            message = ValueBatch(values=[])
+            for i in range(10):
+                value = ValueDescriptor(
+                    signal_id=signal_id, value=2.0, timestamp=monotonic_ns()
+                )
+                message.values.append(value)
 
             future = asyncio.run_coroutine_threadsafe(
                 send_message(