Add crash reporter's init scripts

Part of a three CLs commit that moves crash reporter scripts out of
platform/init.

BUG=chromium:346449
TEST=none

CQ-DEPEND=Ib74673a38ef3886b9b23e2f152dd796a3e29855a
CQ-DEPEND=I079759d0a096c50600c292cc37d3486b1c44e56a

Change-Id: Icaad09443e60ff8dd4527d426cc11204a65c5f96
Reviewed-on: https://chromium-review.googlesource.com/194298
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Tested-by: Bertrand Simonnet <bsimonnet@chromium.org>
Commit-Queue: Bertrand Simonnet <bsimonnet@chromium.org>