Add COMMAND: mute

[DragonMeme]

Please describe feature and reasons for us to add it to the bot.
A command that applies a role with no permissions to communicate with other members in anyway within the guild for a set duration time.

Acceptance criteria:

• Muted User cannot enter/speak voice chat.
• Muted user cannot type/react in any text channels.
• There is a time tracking the duration.
• Ensure that after the timer is up, un-mute the person.
• This event is logged.
• Check that the bot has the permission to manage roles.