[refactor] refactor auth files

branding/config/vendor.conf

branding/scripts/provider.py

branding/templates/bitmaskvpn/config.go

pkg/config/config.go

pkg/vpn/bonafide/auth.go

pkg/vpn/bonafide/auth_anon.go

pkg/vpn/bonafide/auth_sip.go

pkg/vpn/bonafide/bonafide.go

pkg/vpn/bonafide/eip_service.go