add japanese amazon

[jaroslaw-weber]

amazon in japan has different link but page is mostly the same.
enable adding products from local amazon stores

[biancadanforth]

Thank you for the feature request. If we were to ever make Price Tracker a fully fledged Firefox feature, we would certainly want to support as many locales as possible on the biggest e-commerce sites.

I'm going to say what I said in #320 :

Unfortunately, the Price Tracker experiment has not been under active development for many months, and what's more, its maintenance is soon coming to an end (we hope to ship the final update next week which will notify users). All of this is to say that I don't think this good idea will come to pass. :/