* Added dependency on logrus.
* Command line flags are parsed in order to obtain the name of the
configuration file, the log level and the instance identifier.
* Logging in various places : configuration loader, API, data access.
Privilege computations and subsequent actions do not write proper logs
yet.
This is a Go program which can synchronize Graylog 4 roles and access
privileges to dashboards and streams from a LDAP directory, based on a
YAML configuration file that maps LDAP groups to Graylog privileges.
The code is rather ugly, some features are half-baked (LDAP TLS
support, impossible to disable HTTP TLS checks, bad error handling...)
and some documentation needs to be added but it's a start.
