Allow unsharing, only show share controls for owner

internal/conf/templates/view.tmpl.html

@@ -7,15 +7,23 @@
     <a class="btn btn-primary" href="{{.urlEdit}}">Edit</a>
     <a class="btn btn-danger" href="{{.urlDelete}}">Delete</a>
 </div>
+{{ if .isOwner }}
 <div class="mt-2">
     <h3>Ownership</h3>
     {{if .note.Viewers}}
     <p>This note is owned by <em>{{.note.Owner}}</em> and is further visible to</p>
-    <ul>
+    <form action="{{.urlUnshare}}" method="POST">
+    <table class="table vertical-align-middle">
         {{range .viewers}}
-            <li>{{.}}</li>
+            <tr>
+                <td>{{.}}</td>
+                <td class="text-end">
+                    <button class="btn btn-outline-warning btn-sm" type="submit" name="viewer" value="{{.}}">Un-Share</button>
+                </td>
+            </tr>
         {{end}}
-    </ul>
+    </table>
+    </form>
     {{else}}
     <p>This note is owned by <em>{{.note.Owner}}</em>.</p>
     {{end}}
@@ -27,6 +35,7 @@
     </div>
     <button class="btn btn-primary" type="submit">Share</button>
 </div>
+{{end}}
 
 <script>
     let checkBoxes = document.querySelectorAll('input[type=checkbox]')