Loop playlist, repeat song, move songs within playlist

[NowIveAwoken]

After creating your pull request, tick these boxes if they are applicable to you.

• [ x] I have tested my changes against the review branch (the latest developmental version), and this pull request is targeting that branch as a base
• [x ] I have tested my changes on Python 3.5.3 or higher

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Description

This is just my ghetto implementation of adding playlist looping with the loop command, song repeating with the repeat command, and moving songs within the playlist with the move command. I've tested it a bit and so far there have been no issues from the servers I've been running it in but no guarantees that it is bug free.

Related issues (if applicable)

[AutumnClove]

Nice PR, will test it out later tonight, in the meantime we're asking that all new changes have black ran over them. python -m pip install black python -m black {file/s}

[gunplar]

+1 on this. @srhinos do you still support this repo?

[Jcodeerd]

• Is it intended that it keeps looping a song, even when it's skipped?
• !help move doesn't work

everything else LGTM