Add http within the readme file

[Chardonneaur]

The readme file is saying:
./import_logs.py --url=matomo.example.com /path/to/access.log
but if we apply it, it does not work if we are using it with --token_auth, it should be
./import_logs.py --url=https://matomo.example.com /path/to/access.log --token_auth
instead.