- [sass] converted `.l-index-projects.` into `.grey-box` object
- [nj] updated index page to use `.grey-box`
- [nj] replaced `section` with `nav` in `_sidebar-menu` partial
- [sass] updated block-links to color pseudo-links inside on hover
- [nj][sass] added catalog's section page and it's styles
- [sass] updated `style.scss` to use new styles
- [assets] added 3 new svg icons