Merge from Perforce
Migrate functions related to sniffing packet in AP to RucksuAP class
Get original tunnel type from AP not SCG
Fix the bug of AP's retrying to redundancy cluster
Add files of checking configuration/system backup and restore
Exploit decorator pattern to implement the test cases of checking congiuration/system backup and restore
Check AP re-home mechanism when the br0 interface is enabled
Check AP re-home mechanism when the br0 interface is disabled
Check the completion of the SCG restoration
Fix some bugs