Add recipient and sender parameters for individual name parts

[cbobach]

New name related parameters will be added:

• recipient[first_name]
• recipient[middle_name]
• recipient[last_name]
• sender[first_name]
• sender[middle_name]
• sender[last_name]

This will in time push for the deprecation of:

• card[name]
• recipient[name]
• sender[name]

We will in a grace period allow for both old and new parameters, but we recommend that you plan the shift as we can't guarantee how long our upstream provider supports the old fields.

[mt-clearhaus]

Great start! I've added some suggestions and comments.

I think a more appropriate PR title is "Add recipient and sender parameters for individual name parts".

[mt-clearhaus]

A few additional comments 🙂

[mt-clearhaus]

This looks very good to me 👍 We just need to set a date in the change entry.