Add packet capture support in `ConnectivityPacketTracker`

In order to receive APFv6 offload replied packet,
it needs to store the received packets then do pattern match.

add 2 API to control the packet capture
- setCapture() to enable/disable the packet capture
- getMatchedPacketCount() to get the received count by given packet

Test: atest NetworkStackTests
Change-Id: I42f1294e09f622e040fa1a6c67a332ad275a5bda
2 files changed