Add Web UI to generate and revoke bearer tokens

In order for authenticated and authorized users to easily generate and revoke their bearer tokens to lift Web API rate limit, a dedicated Web UI must be added.

The workflow will be the following. When clicking on a "Generate token" button, user will be asked to enter his password again and if it is valid, an offline refresh token will be generated by sending a request to the Keycloak server. This token will then be encrypted, using a key derived from the user password and a salt value, and stored to database.

The UI will also display a list of tokens generated so far by a user and two actions will be offered for each of them: "Show token" and "Revoke token". Those actions will also be protected by the user password.

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Migrated from T2569 (view on Phabricator)