✨(backend) support Authorization code flow

Integrate 'mozilla-django-oidc' dependency, to support
Authorization Code flow, which is required by Agent Connect.

Thus, we provide a secure back channel OIDC flow, and return
to the client only a session cookie.

Done:
- Replace JWT authentication by Session based authentication in DRF
- Update Django settings to make OIDC configurations easily editable
- Add 'mozilla-django-oidc' routes to our router
- Implement a custom Django Authentication class to adapt
'mozilla-django-oidc' to our needs

'mozilla-django-oidc' routes added are:
- /authenticate
- /callback (the redirect_uri called back by the Idp)
- /logout

env.d/development/common.dist

@@ -7,9 +7,6 @@ DJANGO_SUPERUSER_PASSWORD=admin
 # Python
 PYTHONPATH=/app
 
-#JWT
-DJANGO_JWT_PRIVATE_SIGNING_KEY=ThisIsAnExampleKeyForDevPurposeOnly
-
 # People settings
 
 # Mail
@@ -19,5 +16,20 @@ DJANGO_EMAIL_PORT=1025
 # Backend url
 PEOPLE_BASE_URL="http://localhost:8072"
 
-# Keycloak
-SIMPLE_JWT_JWK_URL="http://keycloak:8080/realms/people/protocol/openid-connect/certs"
+# OIDC
+OIDC_OP_JWKS_ENDPOINT=http://nginx:8083/realms/people/protocol/openid-connect/certs
+OIDC_OP_AUTHORIZATION_ENDPOINT=http://localhost:8083/realms/people/protocol/openid-connect/auth
+OIDC_OP_TOKEN_ENDPOINT=http://nginx:8083/realms/people/protocol/openid-connect/token
+OIDC_OP_USER_ENDPOINT=http://nginx:8083/realms/people/protocol/openid-connect/userinfo
+
+OIDC_RP_CLIENT_ID=people
+OIDC_RP_CLIENT_SECRET=ThisIsAnExampleKeyForDevPurposeOnly
+OIDC_RP_SIGN_ALGO=RS256
+OIDC_RP_SCOPES="openid email"
+
+LOGIN_REDIRECT_URL=http://localhost:3000
+LOGIN_REDIRECT_URL_FAILURE=http://localhost:3000
+LOGOUT_REDIRECT_URL=http://localhost:3000
+
+OIDC_REDIRECT_ALLOWED_HOSTS=["http://localhost:8083", "http://localhost:3000"]
+OIDC_AUTH_REQUEST_EXTRA_PARAMS={"acr_values": "eidas1"}