Add oppressive language presubmit

BUG=b:162024466
TEST=try to upload a CL with a blocked term

Change-Id: Ic2a3238ee0c1db580e930222311ade7ad666a9a7
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/libevdev/+/2574802
Tested-by: Harry Cutts <hcutts@chromium.org>
Auto-Submit: Harry Cutts <hcutts@chromium.org>
Reviewed-by: Sean O'Brien <seobrien@chromium.org>
Commit-Queue: Harry Cutts <hcutts@chromium.org>