* Register project structure metadata providers globally, so included
builds can access it from the root build.
* Rework some dependency management logic so that it doesn't assume that
dependencies resolved to projects are safe to access – it is so only
if the project is in the same build; also, in dependency handling, use
proper keys which distinguish project with same ID in different
builds.
* Add a separate implementation of `MppDependencyMetadataExtractor` that
reads the project structure metadata from the mentioned global storage
(as we can't read it from artifacts – those are not yet build at the
project configuration phase) but when it comes to artifacts
processing, takes real artifacts rather than introspect the project
structure.
* Register the Kotlin/Native host-specific metadata artifact
configurations as consumable, so that a consumer from a different
build can properly resolve a dependency to such a configuration and
get the artifact.
Sergey Igushkin
3a5ffe479e