Add new network capabilities to support automotive head unit via USB

- Add a new transport type for USB and a new network capability
to support automotive head unit.
- In order to pass DnsManagerTest#testTransportTypesEqual, Android.bp
needs to link to dnsresolver_aidl_interface-V8-java. That test checks
whether the TRANSPORT types defined in NetworkCapabilities are the
same as IDnsResolver.aidl.

Bug: 181742019
Test: atest FrameworksNetTests
Change-Id: Iec2df09a776d779108f95098e01b7ffdf6f8867a