Portal OAUTH Authentication

You need to add an application in oauth server in order to obtain a client ID and client SECRET
- In case of github, open settings/applications/developer applications then create a new app there
Add support in portal for that application
- installing the package (oauth_client) ays install -n oauth_client -i github
- Now in Login page you should see something like:
- If you need to support extra servers, just install (oauth_client) with a new instance for the server you need to add.
- Information needed while installing oauth_client package:
  - OAUTH SERVER AUTHORIZE URL, i.e; https://github.com/login/oauth/authorize
  - OAUTH SERVER ACCESS TOKEN URL, i.e; https://github.com/login/oauth/access_token
  - REDIRECT URL, (FIXED) http://portal_IP:82/restmachine/system/oauth/authorize
  - SCOPE, i.e; user:email
  - CLIENT ID, In case of github you can get it from the developer application used.
  - CLIENT SECRET, In case of github you can get it from the developer application used.
  - USER INFO URL, the API URL for getting user info, in case of github https://api.github.com/user

Force using oauth only authentication

During installing portal set the "force_oauth_instance" attribute value to the name of the oauth instance you want to force using.

Support for oauth authentication is spread across 3 areas
- @ys package : _clients/oauth_client
- jumpscale client : jumpscale_core7/lib/Jumpscale/baselib/oauth/OauthInstance.py
```
* You can use it from shell using `j.clients.oauth.get(type='github')` 
* replace type by whatever instance you need.
```
- jumpscale portal support
  - actors: jumpscale_portal/apps/system/system__oauth
    - authenticate :/restmachine//system/oauth/authenticate?type=github redirects to certain oauth server
    - authorize : /restmachine//system/oauth/authorize call back api oauth server calls
If username and email returned from oauth server found in osis then user is logged in.
If username is found but email is different than that returned from oauth server, 400 bad request (User already exists) response is returned

During installing portal set the "force_oauth_instance" attribute value to the name of the oauth instance you want to force using.