Add --force flag to cogctl delete/remove commands

[vanstee]

Now that we made many foreign key relationship constraints restrict on delete, we need to add a --force flag to cogctl for convenient operation. We'll also need to support these changes in Cog. Here's a list of all commands that need to support this flag:

• cogctl bundle uninstall
• cogctl users delete
• cogctl groups delete
• cogctl relays delete
• cogctl relay-groups delete
• cogctl roles delete
• cogctl permissions delete

[christophermaier]

This issue was moved to operable/cogctl#133