Support password reset links

[jb3]

Allow a React Router backed route (i.e. /password-reset/:reset-code) to allow users to execute a reset code.

We will need the following:

• Backend route to validate a password reset code and return some limited user information (e.g. name, email)
• Frontend component to render a Cloudflare Turnstile challenge
• Backend code to validate the above tokens when returning user information
• Frontend code to execute a password reset by POSTing to the relevant endpoint and then redirecting to login