Feature: Add multi provider authentification

[syphax-bouazzouni]

Context

See ontoportal/ontoportal-project#26. and lifewatch-eric#5

This PR adds the possibility for the API to validate access token coming from github, orcid, google and keycloak. If the access token is valid. A user is created if not existent with the data returned by the external provider or update the existent user information (to set githubId or orcidId user attributes).

Changes

• Add user oauth2 unit tests (f699f6c)
• Enforce user email attribute to be unique (771cde9)
• Add oauth2 providers configs (6e649f8)
• Implement oauth2 providers token authentication (d1520d3)
• Remove access token authorization to use only the API keys method (f90eefe) from Ontoportal align: Feature: Improve Authentification  lifewatch-eric/ontologies_linked_data#5