Add keycloak backend, better logout instructions & fixes
Features:
- Added a generic OIDC backend. Named 'helusername' as it is targeted towards using Keycloak as an username/password backend.
- Add support for CSP (Content Security Policy)
- Add CORS policy support, with dynamic support for post_logout_uris and redirect_uri
- Add report view for displaying currently configured clients and when they have been used last
- Additional translations
- More logging for e-mail matching problems.
Fixes:
- Verify post logout uri, don't allow arbitrary redirect URIs in logout requests
- Explicitly specify encryption algorithms as a sanity checks, security
- Perform some digest comparisons using using specific functions, security
- Deny frame embeds (X-Frame-Options), security
Maintenance:
- Several dependencies have been updated
- Unused ADFS-integration code removed