Token authentication: display token management view in User center

Currently, the token management (list of tokens, token revocation) is handled in a "Nuxeo Drive" tab of the User center contributed to the nuxeo-drive addon.
It should be externalized in the nuxeo-platform-login-token addon for it to be usable independently from Nuxeo Drive. For example in a "Manage tokens" tab. And therefore token management should be removed from the "Nuxeo Drive" tab.