Allow for formatted duration in wait action

[TheZexquex]

Adds support for formatted durations to the "wait" npc action.
E.g

• 10s
• 5h20m3s
• 16d
  Cloud duration parser seems a bit broken atm, allowing for durations like 10sh or 5hd
  (Edit: This seems to get fixed by this)
  Also milli seconds currently seem not to be supported at all (See https://github.com/Incendo/cloud/blob/3c83f9a680609299894406a2de2502209c16f113/cloud-core/src/main/java/org/incendo/cloud/parser/standard/DurationParser.java#L79-L119)

[OliverSchlueter]

You basically copied the "general" command-methods and made them more specific for the wait action. If we now want to change something about lets say the add action command, we would need to modify two methods. Is there an better option for this? Maybe call the general method with the parsed values of the specific method?

[TheZexquex]

I don't know if calling the original commmand method breaks something in cloud, but i'll try it. We could however at least extract the command logic to a seperat method and call it through both comman methods.