Documentation: Insert API route to user authentication

[manrodrigues]

The endpoint /tokens is not present on our current API documentation (https://getorb.io/api/fleet.html)

This endpoint is very important to use the rest of the API endpoints, since all others require authentication.

We need to insert it, already considering the new authentication using bearer token.

[mclcavalcante]

We need to add one more statement pointing to mainflux's /token endpoint here: https://github.com/ns1labs/orb-website/blob/main/.github/workflows/ci.yml

 - name: redoc-cli user-token
        uses: seeebiii/redoc-cli-github-action@v10
        with:
          args: 'https://raw.githubusercontent.com/mainflux/mainflux/master/api/openapi/users.yml -o docs/api/token.html'

[mclcavalcante]

I believe we should think of a workaround or reconsider adding that to our docs since it's maintained by an external project and may change without our supervision removing or adding unwanted stuff. Plus it contains other endpoints besides /token which is possibly unnecessary to show up on orb docs polluting user's view.

[manrodrigues]

I believe we should think of a workaround or reconsider adding that to our docs since it's maintained by an external project and may change without our supervision removing or adding unwanted stuff. Plus it contains other endpoints besides /token which is possibly unnecessary to show up on orb docs polluting user's view.

I strong believe that this is the best approach for us.