Add support for confirmation APIs.

This code implements new keystore APIs for confirmations.

Also add new 'confirmation' verb to the keystore_cli_v2 command to be
used for testing confirmations. It will block until there's a
callback. Example invocations:

 phone:/ # keystore_cli_v2 confirmation --prompt_text="Hello World" --extra_data=010203 --ui_options=1,2,3
 Waiting for prompt to complete - use Ctrl+C to abort...
 Confirmation prompt completed
 responseCode = 0
 dataThatWasConfirmed[30] = {0xa2, 0x66, 0x70, 0x72, 0x6f, 0x6d, 0x70, 0x74, 0x6b, 0x48, 0x65, 0x6c, 0x6c, 0x6f, 0x20, 0x57, 0x6f, 0x72, 0x6c, 0x64, 0x65, 0x65, 0x78, 0x74, 0x72, 0x61, 0x43, 0x01, 0x02, 0x03}
 phone:/ #

If a prompt is already being shown, the |OperationPending| return code
(code 3) is returned:

 phone:/ # keystore_cli_v2 confirmation --prompt_text="Hello World" --extra_data=010203 --ui_options=1,2,3
 Presenting confirmation prompt failed with return code 3.

Canceling a prompt:

 phone:/# keystore_cli_v2 confirmation --prompt_text="Hello World" --extra_data=010203 --cancel_after=1.5
 Sleeping 1.5 seconds before canceling prompt...
 Waiting for prompt to complete - use Ctrl+C to abort...
 Confirmation prompt completed
 responseCode = 2
 dataThatWasConfirmed[0] = {}

Bug: 63928580
Test: Manually tested.
Change-Id: Ida14706ad066d5350b9081eb7821c7b1a1472dd2
7 files changed