storaged: add storaged native daemon

Storaged periodically checks the devices' disk stats and eMMC lifetime.
This information is logged to both the kernel and event log. By event
logging, the data can be aggregated by the checkin service and then
sent to Sawmill.

It also periodically traverses /proc/[pid], maintaining the I/O usage of
all tasks (all sampled tasks). The task I/O data can be reported using
the --dump option.

Storaged is booted when the device boots up and requires the permission
for reading /proc/diskstats, /proc/[pid]/io and debugfs(eMMC ext_csd).
For detailed description, please refer to go/storaged.

Bug: 28826771
Change-Id: I774b1a44cc30092bac1bfcbc08bf487295e7cfed