feat(home): it's possible to add classes for each page

-- styles for home
feat(boxes): module "boxes"
feat(stages): added stages-module
feat(icons): new type of icons and classes to give each another color
chore(lists): styling for icons in listpoints
chore(navigations): font-size for button in navigation
feat(buttons): class for bigger buttons

-- .m-button--large
chore(grid): remove minus margin-top of l-units
feat(layout): helper for center elements
chore(headings): h2 + h3 gets some styling
chore(presets): some styling for anchors
feat(index): added content