Ubi-config

Changed

- `LocalLoader` is now able to load files from directories with custom names
- Improved `GitLabLoader` logging

Added

- `GitlabLoader` now retries failed requests to GitLab

Added

- Support for flags in config file

Added
- `GitlabLoader` is now more generic and supports custom branch names

Added
- Make ubiconfig.utils.config_validation.validate_config publicly available via
ubiconfig.validate_config

Fixed
- Fix LocalLoader couldn't get right version if the argument version of load() is None.

Fixed
- Fix LocalLoader couldn't populate version field, now it populates the version field
based on directory name.
- Fix remote loader couldn't load all config files with same name from different branches.
- Make version an option argument to Loader.load(), so it could load right version of
config file.