Ping users using send(); Verify improvements

[brandoningli]

Related bugs/feature requests

• Resolves #64

Describe the changes

• Adds a new argument to SpikeKit.send(), an array of Users. Appends mentions for these users before the message content (even with embeds) to ping them.
• Verify now uses this feature
• Prefix not hard coded anymore for verify

Expected behavior

• Verify messages ping the person

Screenshots

New npm dependencies

Testing Instructions

• Already tested. See #bot-commands

Additional context