Support measuring split

measurePackage is changed into measureApk, which would hint that the
method deals with a file instead of a "package" in the package manager's
term.

collectAppInfo is added to measure an app package, which may include
split.

Test
 * Add a test that leverages debug.transparency.bg-install-apps of BICs.
 * Copy BaseInstallMultiple from another test in frameworks/base to
   support split install.

Misc
 * Delete getApexInfo and corresponding unit tests, since it's now
   coverred through collectAllApexInfo in integration test. This also
   makes it easy for refactoring without having to keeping the Bundle
   works as the return type.

Bug: 264296226
Test: atest BinaryTransparencyServiceTest BinaryTransparencyHostTest
Change-Id: Iaa4118dfa8605acda313dbcc2466ae96a60b4721