md-settings: Added settings for fingerprint unlock.

The mocks are not finished yet, but this CL has some of the basic logics implemented. Everything is hidden behind the feature flag QuickUnlockFingerprint.

current mocks - https://docs.google.com/a/google.com/presentation/d/1XEdVznkCAunQKF_AK5bTPgeLFUKmhKp9ntaqm2hKfXY/edit?usp=sharing : Slide 13 - 22

BUG=672269
TEST=NONE
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2538303002
Cr-Commit-Position: refs/heads/master@{#447370}
23 files changed