make mod commands more generic

[xDashh]

add time option and parsing.

chat is /mute|ban <username> <timenumber><m|h|d>
possible bot format !mute|ban<timenumber><m|h|d> <username> or just reuse chat-format.

[jbpratt]

@xDashh I can try this, have you decided on the format? I'm not sure if it makes sense to have two formats for the 'same' commands from the moderator's perspective but there may be plans to adjust the chat format at a later stage.

[tensei]

you can use this to parse time https://github.com/karrick/tparse