tests: add batctl tpmeter test case

tests/test_batctl_tpmeter.py

+#!/usr/bin/env python3
+import sys
+from pynet import *
+import asyncio
+import time
+
+a = Node()
+b = Node()
+
+connect(a, b)
+
+start()
+
+b.wait_until_succeeds("ping -c 5 node1")
+
+addr = a.succeed('cat /sys/class/net/primary0/address')
+result = b.succeed(f'batctl tp {addr}')
+
+print(result)
+
+finish()
+