Improve the latency of DataUsageList

Up to 30x faster.

Currently it load the usage detail for every day at the beginning, so
it's quite slow.

To fix,
- Not load the usage detail for every day at the beginning
- Load only the cycles first
- And only load the daily detail for the selected month

Fix: 290856342
Test: manual - on DataUsageList (cell & wifi)
Test: unit tests
Change-Id: Ie18fa68f801743389bd6b6a28e236dcf1fea00e4