Apps should be able to access the configstore HAL since framework
libraries which are loaded into app process can call configstore.

Letting apps have direct access to this HAL is OK because: 

(1) the API of this HAL does not make clients provide any sensitive 
information to the HAL, which makes it impossible for the HAL to 
disclose sensitive information of its clients when the HAL is 
compromised, 

(2) we will require that this HAL is binderized (i.e., does not run 
inside the process of its clients), 

(3) we will require that this HAL runs in a tight seccomp sandbox 
(this HAL doesn't need much access, if at all) and,

(4) we'll restrict the HALs powers via neverallows.

Test: apps can use configstore hal.

Change-Id: I04836b7318fbc6ef78deff770a22c68ce7745fa9