refactor: move project template to docs

Author: themightychris

site-root/html/projects/template_modal.html renamed to docs/development/add-project.md

@@ -1,3 +1,8 @@
+# Add a project
+
+Use this template to add a new project to `site-root/home.tpl`:
+
+```html
 <!-- Modal TODO -->
 <div class="portfolio-modal modal fade" id="portfolioModalTODO" tabindex="-1" role="dialog" aria-hidden="true">
   <div class="modal-dialog">
@@ -42,4 +47,5 @@ <h2 class="text-uppercase">TODO: Project Title</h2>
           </div>
       </div>
   </div>
-</div>
+</div>
+```