[components][flutter][dart] Combine AOT rules

Combine flutter_aot_component, flutter_aot_package, dart_aot_package
into one set of _component and _package build rules that handle both
flutter and dart components.

Saves code, and enables us to write build rules that drop flutter and
dart components into the same package.

TESTED=
Hardcode dart_default_app and flutter_default_app to "dart_aot_app" and
"flutter_aot_app", then:

run -d fuchsia-pkg://fuchsia.com/echo_dart#meta/echo_client_dart.cmx --server fuchsia-pkg://fuchsia.com/echo_dart#meta/echo_server_dart.cmx
tiles_ctl add fuchsia-pkg://fuchsia.com/simple_flutter#meta/simple_flutter.cmx
tiles_ctl add fuchsia-pkg://fuchsia.com/simple_flutter#meta/leaf_flutter.cmx

ls /pkgfs/packages/echo_dart/0/data/echo_server_dart
ls /pkgfs/packages/echo_dart/0/data/echo_client_dart
ls /pkgfs/packages/simple_flutter/0/data/simple_flutter/
ls /pkgfs/packages/simple_flutter/0/data/leaf_flutter/

CP-142 #comment

Change-Id: I255c4a700e9a752d6c0b8002cb5b2f95996730e2
3 files changed