ConfirmationUI HAL definition

HAL definition for high assurance confirmation providers.
High assurance confirmation providers allow relying parties
to prompt the user for confirming a short piece of information.
If the user confirms, the result is a signed message indicating
that the user has seen the message. For a high assurance confirmation
provider this must also be true if Android and the Linux kernel
are compromised.

Bug: 63928580
Test: VTS tests in the following commit
Change-Id: I72017b39c01b4333d0146c648637a19fafcb7278