Added cooldown command

[davfsa]

Please check the following boxes

• [x] I've read and agree to the Contribution Guidelines and to the Code of Conduct
• [x] I've checked that I didn't commit sensitive information like tokens or other login information
• [x] I haven't hardcoded any IDs or anything else that shouldn't be (with the exception being permissions)
• [x] I tested my code and I verified it's working to the best of my ability (Don't have the ability to do that atm.... but Dougley said he could do it)
• [x] I checked if my code doesn't violate the styleguide with npm test (Travis CI Helped)

Describe your pull request

This pull request will add a cooldown command that will let the custodian know what his xp limits are (this idea was taken from EvilDabbit, in the Discord Testers Server)

[Dougley]

Did you test this? At first glance it looks good.