Add Nextclade section on Splash

Now that sections aren't required to have preview cards, a section for
Nextclade without any cards can visually fit in.

Place it as the 2nd section both due to its importance and because the
abstract length is similar to SARS-CoV-2's, rendering nicely in the
2-column format.

static-site/src/components/splash/index.jsx

@@ -79,6 +79,13 @@ const Splash = () => {
           buttonText="See all resources"
           buttonLink="/sars-cov-2"
         />
+        <Section
+          id="nextclade"
+          title="Nextclade"
+          abstract="Nextclade allows you to analyze virus genome sequences in the web browser. It will align your sequence data to a reference genome, call mutations relative to that reference, and place your sequences on a phylogeny. It also reports clade assignments and quality of your sequence data."
+          buttonText="Go to Nextclade"
+          buttonLink="https://clades.nextstrain.org"
+        />
         <Section
           id="groups"
           title="Nextstrain Groups"