[Feature Request] Pin the "now playing" message

[Wolfhound905]

Is your feature request related to a problem? Please describe. This is not related to a problem.

Describe the solution you'd like When the user types <prefix> nowplaying then the message should be pinned in the music tc that was set by the user. The message should be unpinned when the user stops the bot or music has run out or the user types <prefix> nowplaying again.

Describe the basic flow/steps of using this feature How this feature would be used:

1. Type <prefix> nowplaying

Additional context

Please check the following links to confirm that your feature has not already been requested: https://github.com/jagrosh/MusicBot/labels/enhancement https://github.com/jagrosh/MusicBot/wiki/Things-That-Won%27t-Be-Added