Move dexpreopt processing from java_*_import to prebuilt_apex

dexpreopt of apex system server from prebuilts involves three soong
modules
1. prebuilt_apex / apex_set
2. an internal deapexer module created by the prebuilt apex
3. java_import/java_sdk_library

(3) acts as a shim for the deapexer to set the dexjar extracted from the
prebuilt apex. This methodolody requires a 1:1 correspondence across the
three modules

This breaks down when we have multiple versions of the same prebuilt
apex in the tree. In preparation for this, move the dexpreopt
processing from (3) to (1). Each prebuilt_apex will create the necessary
rules for dexpreopting the jars deapexed from itself. In the future,
apex_contributions will be used to pick which service-foo.{odex|.vdex} to
install depending on which prebuilt apex is selected.

Implementation details
- Embed dexpreopter in prebuiltApex structs so that this module type can
  register the dexpreopt rules. Since a single apex can have multiple
  system server jars, this also requires creating an additional scope in
  dexpreopt.go to prevent name collisions
- Add the dexpreopt modules as required in initApexFilesForAndroidMk
- Add the depreopt modules to androidMk in AndroidMkEntries. Drop the
  equivalent from java_import and java_sdk_library_import

Bug: 308790457
Test: existing soong unit tests
Test: lunch cf_x86_64_phone-next-userdebug && m out/target/product/vsoc_x86_64/system/apex/com.google.android.adservices.apex
Test: Verified that the above command installs
/out/target/product/vsoc_x86_64/system/framework/oat/x86_64/apex@com.android.adservices@javalib@service-adservices.jar@classes.{odex|vdex} and the equivalent files of service-sdksandbox

Test: presubmits

Change-Id: I01cea8956d2857fb864b415e73d3d2686d069b5e