Introduce PreapprovalDetails class (1/n)

In order to let developers to get the install approval from users
pre-download instead of post-commit for better UX, introduce the
new data class PreapprovalDetails to encapsulate all the necessary
data for the upcoming installation.

Bug: 242677131
Test: build
Test: atest CtsContentTestCases:PreapprovalDetailsTest
Change-Id: I29a364262f980d5e30c4800fa0cfb2caae8ffa79