Roundcube plugin: user_config

This plugin enables user-specific configuration files, which is analogous to Roundcube host-specific configuration through built-in setting 'include_host_config' (an example on how to use this feature is described at https://github.com/roundcube/roundcubemail/wiki/Configuration:-Multi-Domain-Setup). Configuration files will be loaded from the global configuration directory. See user_login plugin example configuration (config.inc.dist) for more details. This plugin can be used to enable new plugins (in addition to those enabled in the main configuration) on a per-user basis, however it will not be possible to disable plugins from the main configuration as they will already be loaded at the time of loading user-specific configuration files. User to configuration file mapping is based on Roundcube usernames, which may or may not contain a domain part.