feat: apply content corrections by ealloza, such as update h12o-isaric diagram and add several paragraphs

refactor(#16): avoid loading several times the datatables js/css bundles; load them only once in head.html and foot.html

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

style(#16): apply some style on search inputs in datatables; place search boxes and download buttons in the same row next to each other

refactor: update isaric-based variables with 12Octubre model & modify content / layout / partial on this section

refactor: replace h2 texts in home page with i18n variables; feat: change card style for research projects in home page and increase from 3 to 4 the number of cards per row

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')

refactor!(#5): deep re-structuring of the whole HUGO project; more descriptive filenames in both content and layouts; add contrast color and underline in active section inside the top menu; remove breadcrumbs and banner for every section