Recipe slash command parsing

[katzdave]

Summary

Currently we split parameters at spacebar, and only the first word is sent to the first param.

Now everything is parsed as the first param (without a default, or just the first if they all have defaults).

If there are more than 2 required params, throw an error; I think this case is pretty hard to handle without some richer parameter filled UI; Since you aren't directly looking at the recipe you have little hope of remembering all the param names.