Add back single command target

[HashimTheArab]

Many commands require a single target such as things like ban, setrank, mute, etc. Having to treat every command as multiple targets is very inconvenient, this was discussed before and I said I would add it but got busy

[Sandertv]

I'm still not entirely convinced these "require" a single target

[JustTalDevelops]

I feel like this should be readded also.

I think, while it is easy to 'reproduce' single target functionality yourself, it creates quite a lot of duplicate and unnecessary code over a lot of commands versus having some sort of built-in type to handle them - for basically no cost on our part.