appview/pages: auto-select knot when there's only one

Signed-off-by: Jordan Reger <[e-mail]>

appview/pages/templates/repo/fork.html

···
                 value="{{ . }}"
                 class="mr-2"
                 id="domain-{{ . }}"
+                {{if eq (len $.Knots) 1}}checked{{end}}                
                 />
             <label for="domain-{{ . }}" class="dark:text-white">{{ . }}</label>
           </div>

appview/pages/templates/repo/new.html

···
             class="mr-2"
             id="domain-{{ . }}"
             required
+            {{if eq (len $.Knots) 1}}checked{{end}}
           />
           <label for="domain-{{ . }}" class="dark:text-white lowercase">{{ . }}</label>
         </div>