Add hook support to plugin implementation

[chrisroberts]

Components need to have action hooks defined and must be accessible via plugin interface. These are defined as action hooks in the plugin documentation: https://www.vagrantup.com/docs/plugins/action-hooks

Most plugins rely on hooks to signal that they need to do something (like perform a check or execute a command at a given point in the process). The cloud command and the NFS synced folders both use hooks to perform different tasks (cloud uses it for applying auth, NFS uses it for /etc/exports cleanup). This can be considered working when these plugins can be ported fully, successfully.