web: remove build navigation buttons, enable direct ZIP download

The gunicorn does not let us host directories like apache. Also, it
makes more sense to serve the build artifact archive as a zip to users
instead of letting them roam around inside the builds directory.

web/static/js/index.js

@@ -79,8 +79,8 @@ function updateBuildsTable(status_json) {
                                     <button class="btn btn-md btn-outline-primary m-1 tooltip-button" data-bs-toggle="tooltip" data-bs-animation="false" data-bs-title="View log" onclick="launchLogModal('${build_id}');">
                                         <i class="bi bi-file-text"></i>
                                     </button>
-                                    <button class="btn btn-md btn-outline-primary m-1 tooltip-button" data-bs-toggle="tooltip" data-bs-animation="false" data-bs-title="Open build directory" onclick="window.location.href = '/builds/${build_id}';">
-                                        <i class="bi bi-folder2-open"></i>
+                                    <button class="btn btn-md btn-outline-primary m-1 tooltip-button" data-bs-toggle="tooltip" data-bs-animation="false" data-bs-title="Download build artifacts" onclick="window.location.href = '/builds/${build_id}/${build_id}.tar.gz';">
+                                        <i class="bi bi-download"></i>
                                     </button>
                                 </td>
                             </tr>`;

web/templates/add_build.html

@@ -39,7 +39,6 @@
             </div>
             <div>
                 <a href="https://github.com/ArduPilot/CustomBuild/issues/new" class="btn btn-outline-light me-1"><i class="bi bi-github me-2"></i>Report an issue</a>
-                <a href="/builds/" class="btn btn-outline-light me-1"><i class="bi bi-folder2-open me-2"></i>Go to builds directory</a>
                 <a href="/" class="btn btn-primary"><i class="bi bi-eye me-2"></i>View all builds</a>     
             </div>
         </div>

web/templates/index.html

@@ -42,8 +42,6 @@
                     <div>
                         <a href="https://github.com/ArduPilot/CustomBuild/issues/new" class="btn btn-outline-light me-1"><i
                                 class="bi bi-github me-2"></i>Report an issue</a>
-                        <a href="/builds" class="btn btn-outline-light me-1"><i class="bi bi-folder2-open me-2"></i>Go to
-                            builds directory</a>
                         <a href="/add_build" class="btn btn-success"><i class="bi bi-plus-square me-2"></i>Add a build</a>
                     </div>
                 </div>