This exports FuSecurityAttrs into libfwupdplugin so that we can pass the plugins
this object rather than a 'bare' GPtrArray. This greatly simplifies the object
ownership, and also allows us to check the object type before adding.
In the future we could also check for duplicate appstream IDs or missing
properties at insertion time.
This change also changes the fu_plugin_add_security_attrs() to not return an
error. This forces the plugin to handle the error, storing the failure in the
attribute itself.
Only the plugin know if a missing file it needs to read indicates a runtime
problem or a simple failure to obtain a specific HSI level.
