Generalize native person fields

[richardolsson]

Native person fields appear all over the place, but the translations and some other basic utilities are repeated over and over. I'm thinking about:

• Localizations of the native field labels
• List of NATIVE_FIELDS
• Logic to display fields belonging to a person, regardless of native or custom

All of these should be generalized and reused across various features like PersonPane, JoinSubmissionPane, views et c.

[richardolsson]

"Native fields" refer to those person fields which are not custom and hence exist in all organizations. Native fields include first_name, last_name, email, phone etc.