Allow exporting of sdk members to be done per tag

Previously, every module added to an sdk directly through one of the
SdkMemberType specific properties, e.g. java_libs, was exported and
every module added automatically via a transitive dependencies was not
exported. This change allows that behavior to be customized per tag.

Bug: 186290299
Test: m art-module-sdk
      - verify that this change does not affect its contents.
Change-Id: I563b5bcd823e61c23cdb706cfcbb13337963d550