Refactor java compileDex

We want to support a compile_dex property for java_import. This splits
dex-related properties into a dexer struct which can be embedded in
relevant modules.

Test: m
Test: soong tests
Bug: 160455085
Merged-In: If56a51dac43f630d49483a36db29cd50e9ccd529
Change-Id: If56a51dac43f630d49483a36db29cd50e9ccd529