Rework how to add new details

[jancborchardt]

Currently you need to use the very strange dropdown in the bottom to use any kind of new field.

Instead we should do it like iOS and Android (and probably others) that the normal sets of fields like phone number, email, address etc have an entry directly below to »Add new phone number« etc. These sets of fields should of course be visually separated by whitespace and also need a header. Which we are missing anyway at the moment, which makes it very confusing.

Then the dropdown at the bottom would only be used for adding fields which are not the defaults, like notes, anniversary etc.