Added required scripts loading support to QtScriptResolver.
The good:
 * you can now add multiple scripts to be loaded for a single resolver before the main script, specified in metadata.json in a bundle.
The bad:
 * it adds some complexity, and it's not tested at all.
The ugly:
 * passing configuration from ResolverAccountFactory as QVariantHash, but that's not new,
 * changing ResolverFactoryFunc,
 * an added optional QStringList parameter to Pipeline::addScriptResolver,
 * the inevitable uselessness of this parameter in ScriptResolver.