Add the new RIL requests and NetworkScanResult.

Those new RIL requests will be used to start and stop network scan, and
the scan result will be returned from RIL in the format of
NetworkScanResult.

Test: Telephony sanity tests
Bug: 30954762
Merged-in: I2bfd0fb8cbb3815cc62ec4385594dec9c5e4d279
Change-Id: I2bfd0fb8cbb3815cc62ec4385594dec9c5e4d279
(cherry picked from commit b36a4cb4)
(cherry picked from commit 84c9e01f)