Add sortable table of all countries

[pgriggs]

• use Ant Design table component https://ant.design/components/table/

• Add to a new homepage section below the current page section

• refactor existing timetoherd.jsx component to conditionally return a raw number for each variable to be used in the table (currently, it only returns a number wrapped in an animated component CountUp - but this makes it not useable for a sortable table)

• row data:

• Country Name
  -Time until Herd Immunity
• % of Population Vaccinated

• of Vaccine Doses Given

• % of Population Vaccinated per Day (7-day MA)

• of Doses Given per Day (7-day MA)