Change AuthorizationSetBuilder methods to separate padding, etc.

Padding and digest are now repeatable, so it doesn't make sense to have
builders that take only one. MAC length is also no longer a key
characteristic, so it doesn't belong in the key builders.

Bug: 19509156
Change-Id: Ie4d524ef2c46a0dd62a628d95bed456bcf85a4f3
3 files changed