feat: add forecast-eval to covidcast footer

Author: sgratzl

themes/delphi/layouts/partials/footer.html

@@ -8,6 +8,7 @@
         <h5 class="uk-text-bold">COVIDcast</h5>
         <ul class="uk-list">
           <li><a class="uk-link-text uk-text-small" href="{{ relref . "/covidcast" }}">Overview</a></li>
+          <li><a class="uk-link-text uk-text-small" href="{{ relref . "/forecast-eval/" }}">Forecast Evaluator</a></li>
           <li><a class="uk-link-text uk-text-small" href="{{ relref . "/covidcast/surveys" }}">Surveys</a></li>
           <li>
             <a class="uk-link-text uk-text-small" href="{{ relref . "/covidcast/survey-results" }}">Survey Results</a>