runner: fixed spacing in logging
portage3: add 'settings_home' method

'settings_home' returns path to the main 'make.conf' file
311_global_use_flags: 2 changes

1. use new method to get path of make.conf
2. drop useless line
301_system_settings: full rework

1. split into 2 separate scripts
2. use data from 'emerge_info' file
3. gracefull work on non Gentoo PCs