Improve the dependency resolution in OSGi Plugins

The package scanner currently returns the version of the first jar it finds with the given package inside it.
This has two main problems:

• The version number found for a given package is non-deterministic
• If it finds a jar with no version information first, then we have no version information and this can cause errors on startup.
  Also, we should include meaningful warnings when multiple versions are found for a given package.

The error message on dependency resolution fail could be made more user-friendly and include extra information needed to resolve the issue.
eg: If we fail to resolve a particular version of a dependency, then we could log all the available versions.