sepolicy: New sepolicy classes and rules about bpf object

Add the new classes for eBPF map and program to limit the access to eBPF
object. Add corresponding rules to allow netd module initialize bpf
programs and maps, use the program and read/wirte to eBPF maps.

Test: no bpf sepolicy violations when device boot
Change-Id: I63c35cd60f1972d4fb36ef2408da8d5f2246f7fd