request: remove all usage of discord.js's utils

[kyranet]

Is your feature request related to a problem? Please describe.
Once we migrate to KlasaCore, we won't have the same utils. Therefore we should switch them with Klasa's utils and/or port those that aren't given by Klasa.

Describe the solution you'd like
Remove all usage of discord.js's utils.

Describe alternatives you've considered
N/a.

Additional context
In some places we use djs's Snowflake utils, we should switch that for @klasa/snowflake, and same thing for everything else.