style(#16): edit buttons avoiding EBI-like style; correct behaviour when hover on sections links on second navbar

refactor(#4): replaced and cleanup styles.css by several _modules.scss in assets/sass/; refactor(images): relocate image resources (png, svg) into new directory images/, rename images following the easy-to-write kebab-case-convetion; refactor(proposal): change style of cards in resources section

refactor: change user consent acceptance from localStorage to document.cookie; feat(ui): change appearance of all call-to-action buttons (for example, 'Download table as CSV')