Adds passport-saml as local library

Adds passport-saml from https://github.com/bergie/passport-saml
as passport-saml-dynamic-idp.
Adds dependencies for passport-saml
Adds support for defining the IdP in the runtime

- Provides a basic model for IdPs as a mongo collection
- An IdP can be passed to the library dynamically by using the
  parameter idp. The value should be a valid entityId.
Seeds the IdP mongo collection with 2 IdPs

- Adds GRNET VHO
- Adds Feide OpenIdp
Changes DiscoJuice initialization

- Uses DiscoJuive.Hosted.getConfig instead of DiscoJuice.Hosted.Setup
  in order to be able to override default configuration
- Adds Feide OpenIdp
- Fixes configuration for local SP
Adds default passport-saml config and routes

- Adds /saml/login and /saml/login/callback routes
- Adds default passport-saml configuration initialization
- Expects configuration in local.json. E.g.
```
"passport": {
    "saml": {
      "path": "/saml/login/callback",
      "entryPoint": "https://openidp.feide.no/simplesaml/saml2/idp/SSOService.php",
      "issuer": "https://127.0.0.1:8081/saml2/entityid"
    }
  }
```
Merge branch 'master' into edugain_integration
Moves the saml callback code to a separate route

Following the example of login.js

TODO: Investigate using just login.js both for local and saml logins
Uses login.js both for local and saml logins
Merge pull request #51 from skanct/edugain_integration

Edugain integration