Signup payload as specified by SimpleSignupData.
Callback called if signup was successful.
Callback called if signup failed. Content contains Array of Objs with errorKeys (i18nKey) and errorTypes (type)
List of errors
Issue list may contain several issues. Not just one item.
In Case of Error with status 400 theres is no way to by pass of fix via user input.
Issue list may contain several issues. Not just one item.
Perform signup with the given data and callbacks.