Rearrange Clone Panel (#31142)

Rearrange the clone panel to use less horizontal space.
The following changes have been made to achieve this:
- Moved everything into the dropdown menu
- Moved the HTTPS/SSH Switch to a separate line
- Moved the "Clone in VS Code"-Button up and added a divider
- Named the dropdown button "Code", added appropriate icon

---------

Co-authored-by: techknowlogick <techknowlogick@gitea.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

web_src/css/repo/clone.css

@@ -0,0 +1,32 @@
+/* only used by "repo/empty.tmpl" */
+.clone-buttons-combo {
+  flex: 1;
+}
+
+.clone-buttons-combo input {
+  border-left: none !important;
+  border-radius: 0 !important;
+}
+
+/* used by the clone-panel popup */
+.clone-panel-field,
+.clone-panel-list {
+  margin: 10px;
+}
+
+.clone-panel-tab .item {
+  padding: 5px 10px;
+  background: none;
+}
+
+.clone-panel-tab .item.active {
+  border-bottom: 3px solid var(--color-secondary);
+}
+
+.clone-panel-tab + .divider {
+  margin: -1px 0 0;
+}
+
+.clone-panel-list .item {
+  margin: 5px 0;
+}