Make sure configFile in features makes config available early

We currently have the config and configFile elements in feature files.
Config writes the given entries to ConfigAdmin while configFile writes a file.

So configFile is needed if the user should get a nice file to edit. The problem with configFile is that ConfigurationAdmin reads the files asyncronously. So bundles of the feature might already be started at the time the config is written.
So bundles might need to restart or if they only process the config once are in a kind of invalid state that does not relfect the config from the feature.

So I propose to also write the config to ConfigAdmin if configFile is used. This should allow the bundles to come up in the correct state from the start.