AAPT2: Emit more proguard keep rules for layouts and menus

<fragment> tags in layouts use the class attribute to determine which
Fragment subclass to load, and fallback on android:name if class is not
set.

AAPT2 only emitted a proguard rule for the class attribute for <fragment>,
when it should emit a proguard rule for the android:name attribute as
well.

AAPT2 didn't handle menu XML, so support for actionViewClass,
actionProviderClass and onClick is added.

Bug: 62216174
Test: make aapt2_tests
Change-Id: Ie8675c2bd899a5b51f3661eb0901ab8c9a16fd70