API access token management

[sblack-usu]

Describe the feature you'd like and what it will do
As a user I'd like to generate and delete access tokens for my user to be used with the API. A simple UI for managing these tokens would make it easier to manage these tokens.

Why is this feature important?
Currently a user has to use the same access token that is used on the site. This currently can be read from a cookie stored in the browser or read from the response of the login endpoint.

Is your feature request related to a problem? Please describe.
I'm always frustrated when I have to read a raw response in a browser.