bootstat: Move bootstat to its own subdirectory.

bootstat should not be compiled with libchromeos.
This also replaces the old Makefile with a gyp file.

BUG=None
TEST=Unittests
TEST=trybot run on lumpy-incremental daisy link gizmo chromiumos-sdk.

CQ-DEPEND=CL:289240

Change-Id: I0c11fa53edbec6c8be9aa93ba8ebc38a051fac79
Reviewed-on: https://chromium-review.googlesource.com/289214
Tested-by: Bertrand Simonnet <bsimonnet@chromium.org>
Reviewed-by: Christopher Wiley <wiley@chromium.org>
Commit-Queue: Bertrand Simonnet <bsimonnet@chromium.org>
Trybot-Ready: Bertrand Simonnet <bsimonnet@chromium.org>
13 files changed