command.py: add resolve option for generateTargetsTree API

command.py: add resolve option for generateTargetsTree API

Currently we have generateTargetsTree API, which is used to get
dependency information. However in that tree, there will be
"virtual/xxx" in depends fields. Therefore we add the resolve option
to replace it with its real providers.

Besides, for packages that provided by multiple recipes, we will find
their preverred provider.

(Bitbake rev: 28501612efdfc6ee47576cc90deb6e897883e7f5)

Signed-off-by: Dongxiao Xu <dongxiao.xu@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>