identity: Add support for setting minimum validity period for AuthKey.

This change adds support for specifying that an AuthKey should be
replaced if it's going to expire within a certain amount of time
configurable by the application. This also adds a way for the
application to learn about the expiration time of currently configured
AuthKeys.

Combined these two changes allow an application to get a perfect
picture of which AuthKeys are available, when they expire, and allows
the application to refresh AuthKeys well ahead of expiration dates.

Also remove wrong comment that storeStaticAuthenticationDate() variant
taking an expiration is only available in feature version 202101. It's
available on all feature versions.

Bug: 241912421
Test: atest VtsHalIdentityTargetTest
Test: atest android.security.identity.cts
Change-Id: Ib79da64abfa25b37ed73a37ce78fedd4ef7d1ece