Move CryptKeeper to own process

It is possible to run settings from within keyboard, and then find ways of
crashing it. This restarts CryptKeeper since they are one process, with
bad consequences (see bug).

Move to separate process to alleviate this problem

Bug: 21514179
Change-Id: Ib2c19e8f0f3956402cc11a2caedc0a45f786cac3