fix(accessibility): nav element + avoid p element for presentation (asqatasun issues)

...components/needs-selection/needs-selection.component.html

src/app/header/header.component.html

src/app/header/header.component.scss

src/app/shared/components/modal/modal.component.html

src/app/shared/components/modal/modal.component.scss

src/app/shared/components/nav-bar/nav-bar.component.html