Add support for AzureADTenantOAuth2 backend which allows restricting
authentication to a specific Azure AD tenant (organization).
Configuration:
- SOCIAL_AUTH_AZUREAD_TENANT_OAUTH2_KEY: Azure app client ID
- SOCIAL_AUTH_AZUREAD_TENANT_OAUTH2_SECRET: Azure app client secret
- SOCIAL_AUTH_AZUREAD_TENANT_OAUTH2_TENANT_ID: Azure AD Directory ID
This enables organizations to restrict Tabby Web access to only users
from their Azure AD tenant, preventing personal Microsoft accounts or
users from other organizations from logging in.
Fixes#120