Replace "first name" with "given name" and "last name" with "family name"

In order to abide by the web content accessability guidelines we should refactor these personal attributes in the following way:

• first name to given name
• last name to family name
• short name to nickname

An alternative would be to override the name given by the form which can be quite messy.

added part::backend type::refactoring labels

marked this issue as related to #101 (closed)

changed the description

added workflow::discussing label

The fields are designed to be a 1:1 mapping of Django's User object. I would not readily diverge from that.