Change "Blink Address" to "Lightning Address" in all places

[agbegin]

User feedback: Hey Andrew, we refer our users to Blink but we hear from them that they find it hard to find the lightning address. Just thought I’d share some feedback from our users about your product. Perhaps this has to do with the fact that you guys call it ‘pay code’, while we refer to it as ‘lightning address’.

User recommends changing from "Paycode", but this may warrant a bigger discussion. A more simlpe and straightforward fix to the problem of Lightning Address being hard to find is to call it Lightning Address in the settings screen, and anywhere else we call it "Blink Address"