feat: add contact email field for individuals, add privacy notice (resolves #8)

[greatislander]

• [x] I've read the guidelines for Contributing to the Platform Co-op Toolkit
• [x] This isn't a duplicate of an existing pull request

Description

This PR adds a new contact email field to the user profile for public display, and adds privacy notices to both individual and organization profile creation flows.

Steps to test

1. Create/edit/view individual profile with contact email.
2. Create organizational profile.

Expected behavior: Both profiles creation forms display an appropriate privacy notice. Email link is added to individual profile.

Additional information

Not applicable.

Related issues

Resolves #8.