[WIFICOND][API] MacAddress + capability flags

Per API council feedback:
- Convert: byte[] -> MacAddress
- Formalize capability bit flags

Bug: 149105833
Test: atest android.net.wifi
Test: atest com.android.server.wifi
Change-Id: I3e65511eec9b8d5ebc829de34b386b600ed67e82
5 files changed