Add fronted functionality for 'forgot password'

[codingfabi]

When a user forgets his password he needs to be able to reset it without logging in. While there is a backend endpoint for it, it also needs to be implemented in the frontend.
There already exists a link for it, it just has to link to a page to enter an email and then send a backend request to reset the password.

See 'forgot password?' link under the form