feat(tpl): add login link

Author: marjune163

src/tpl/defaultTheme/frontend/index.css

@@ -162,6 +162,13 @@ html.dragging::before {
 	display: none;
 }
 
+.login {
+	position: absolute;
+	z-index: 1;
+	right: 0;
+	padding: 0.5em 1em;
+}
+
 .tab {
 	display: flex;
 	white-space: nowrap;

src/tpl/defaultTheme/frontend/index.html

@@ -20,7 +20,9 @@
 	<li><a href="{{.Path}}{{$contextQueryString}}">{{fmtFilename .Name}}</a></li>
 	{{end}}
 </ol>
-
+{{if .LoginAvail}}
+<a class="login" href="{{if ne .Status 401}}{{.RootRelPath}}?auth={{.Path}}{{$contextQueryString}}{{end}}">{{.Trans.LoginLabel}}</a>
+{{end}}
 {{if .CanUpload}}
 <div class="upload-status">
 	<span class="label info">