Added Commands

I implemented a few more commands:

ruleset check: Check if the ruleset is valid
ruleset create: Create a new ruleset
ruleset edit: Open the ruleset YAML file in the default editor
ruleset list: List all rulesets

group create: Create a new group
group edit: Open the group YAML file in the default editor
group add-set: Add the ruleset to the group
group remove-set: Remove the ruleset from the group
group list: List all groups