New autofill APIs: DateTransformation and DateValueSanitizer.

These APIs are useful when an app uses a date value for a credit card
expiration date.

Test: atest CtsAutoFillServiceTestCases:DateValueSanitizerTest \
            CtsAutoFillServiceTestCases:DateTransformationTest \
            CtsAutoFillServiceTestCases:CustomDescriptionDateTest

Fixes: 72450441

Change-Id: Ie17ab17aa07e0401f4dbba3faa80cc2cc2e7d783