Account email management

## The feature
Currently, there doesn't seem to be a way to change your account email. My account is signed in via GitHub, where I have changed my primary account email from an old email to a newer email, and I log-in with the old email and my password. I would like the ability to log-in with my new email, which is currently not possible.

## Detailed explanation
This feature could include an account management dashboard where you could:
- Manage which account connections are associated with your account (e.g. Google/GitHub).
- Remove account connections.
- Change your password (already possible on the sign-in page, but could be done on this dashboard as well).
- Change your e-mail.

## Mockups

### Home screen

A screenshot of Adobe's account management dashboard home screen. The user's email, time since last password change, and current social sign in are shown. Social sign-in icons are active or greyed out depending on social connection status.

### Profile page

A screenshot of Adobe's Account management dashboard's profile page. You can edit the primary email and secondary email by clicking a "Change" button, and it shows whether the email is verified with "Verified" text under the email.

### Sign-in and security page

A screenshot of Adobe's Social sign-in management. You can disconnect/connect accounts with the "Disconnect/Connect" buttons and see the date each account was connected.

Start with the existing sign-in page and authentication flow, then compare their current behavior with the requested account-management dashboard and the supplied mockups. Done means users can manage linked Google/GitHub connections, change their email and password, and see the relevant account status.

Written by the indexing model from the issue text.