Add "drush fr" command

Committed to 87be9cc.

This was pretty straightforward. But a couple of notes:

1. Requires a patch to config_update here: #2455897: Need to allow setting a custom ExtensionInstallStorage to fix the issue with profiles always overriding the extension config
2. Added a helper function for getting a feature package that allows $any to work with modules not actually marked as "features". This allows the "drush fd" and "drush fim" (drush fr) commands to be used with normal modules to look at config differences and import their updated config

TO DO

Still to-do is to handle *new* config that isn't in the active store yet. The current call to config_update revert assumes the config is already in the active store. Need to call the config_update import function for new config.

Commit db9cfd2 changes this to use the newer patch (#5) in #2455897: Need to allow setting a custom ExtensionInstallStorage

Commit 1ca87b1 changes this to use patch #10 in #2455897: Need to allow setting a custom ExtensionInstallStorage which looks like the one to be applied.