[Thread] add Thread network permissions

Defines permissions for guarding access to Thread network API.

The permissions are also granted to shell for CTS tests, see the
instructions here: go/ctswrite#write-a-test-to-test-an-api-that-requires-system-permission

Design doc: go/thread-android-api

Bug: 262683651
Merged-In: Ib15d5589bbd304d68840ee52a193676d12110512
Change-Id: Ifc6c1d55cc170a5a200dfb5d531f5e0f86a9507a