i18n logistration

This is i18n of all things logistration. I've included translator's comments where possible to make the usage of strings clear. As far as myself, Sarina, Andy, and DB know, there's no good way to include translator's comments in our Underscore templates; I'm open to suggestions on this.

@AlasdairSwan and @dianakhuang, could one of you take a look at this when you have a moment?
Minor nitpicking point but as the rest of the file uses single quotes for strings I would prefer to remain consistent. There is also an argument that single quotes are marginally faster to process than double quotes, but mainly I want to retain consistency across a file (so the same comment stands for the other JS files that you have updated).