package.bbclass: Improve shlibs needed data structure
Improve the shlibs 'needed' data structure to include the file and
any rpath information. This allows various cleanups to the data structure
and moves us closer to being able to resolve shlibs providers issues
based on path in due course.
This commit doesn't change any stored data, just cleans up internal data
structures (for example dropping the needed_from dict).
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
