Translation: missing strings + sign up confirmation message

[severinmenard]

When creating an account with the in French (100% translated in Transifex), a message in English shows up when having filled the info, informing that "A message with a confirmation link" has been sent to the email address (do not remember the exact text).
The message sent to the email box is also only in English, would be good to include this text into the ones that can be translated with Transifex

[mataharimhairi]

@severinmenard this issue is related to #67 and is aimed to be streamlined in the re-write.