ConnectivityService: improve wakelock logging

This patch adds the following wakelock related counters to connectivity
service dumps included in bug reports:
 - total number of wakelok acquisitions and releases
 - total cumulative wakelock duration
 - longest time the lock was held

Bug: 65085354
Test: runtest frameworks-net, also manually dumped connectivity service
      and check new logging

Change-Id: I8f67750c2eea73abf3d44f7f6df484427a8ea3f9