Update Key model

[marceloomens]

Update the Key model with additional fields:

• Selected by default (default)
• Name (name)
• Title (title)
• Biography (bio)

I might add a biography field in order to keep the semantics of the current description (desc) field.

[marceloomens]

I've added the default field but will leave the name, title, bio (and avatar) fields for later. The default field is enough to satisfy the Form customisation epic.