Feature: Add multi provider authentification

[syphax-bouazzouni]

Context

See https://github.com/ontoportal/ontoportal-project/issues/26. and https://github.com/lifewatch-eric/ontologies_linked_data/pull/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 (https://github.com/ontoportal-lirmm/ontologies_linked_data/commit/f699f6ce70c2b5bc20536012d7a9a085e42dfd72)
• Enforce user email attribute to be unique (https://github.com/ontoportal-lirmm/ontologies_linked_data/commit/771cde98d4b44a21a1445421f049a2463a9b0758)
• Add oauth2 providers configs (https://github.com/ontoportal-lirmm/ontologies_linked_data/commit/6e649f8a64c7a25a59fb010388a3d6004ed08e87)
• Implement oauth2 providers token authentication (https://github.com/ontoportal-lirmm/ontologies_linked_data/commit/d1520d30312f88843bc10d8dd68e3c7d890c547d)
• Remove access token authorization to use only the API keys method (https://github.com/ontoportal-lirmm/ontologies_linked_data/commit/f90eefe4a21bbe33a26455f88b79658675f8eb32) from https://github.com/lifewatch-eric/ontologies_linked_data/pull/5