API Explorer needs to authenticate for API calls

If AAA is installed/enabled, the API Explorer "Try out" functionality will return a 401 (unauthorized), because Restconf requires authentication.

To authenticate, there are 2 methods:

1) Allow a token header to be submitted (similar to the api_key in SwaggerUI) with the request. The token is in the form of: "Authorization: Bearer <token>". The token can be retrieved by doing a POST to AAA as such:

curl -s -d 'grant_type=password&username=admin&password=admin&scope=sdn' http://<controller>:8181/oauth2/token

2) Use basic auth with "admin/admin".

The first method is preferred.