bitbake: utils: Add explode_dep_versions2 to replace explode_dep_versions

bitbake: utils: Add explode_dep_versions2 to replace explode_dep_versions

The API for explode_dep_versions is flawed since there can only be one version
constraint against any given dependency. This adds a new function with an API
without this limitation. explode_dep_versions() is maintained with a warning
printed when its used in a situation where information is lost.

This should allow a simple transition to the new API to fix the lost dependency
information.

join_deps() is updated to deal with data in either format.

(Bitbake rev: babeeded21827d8d3e7c7b785a62332ee9d45d4f)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>