Private pastes, systemd unit file, design updates.

It is now possible to create private pastes, just check approriate
checkbox.

Added systemd unit file. Don't forget to fix it for your needs!

Updated design for pastes viewing, now paste information shows in
table. Improves mobile experience at least :).

assets/index.html

@@ -6,6 +6,7 @@
     <meta name="viewport" content="width=device-width, initial-scale=1">
     <title>Fast Paste Bin</title>
     <link rel="stylesheet" href="/static/css/bulma-0.7.0.min.css">
+    <link rel="stylesheet" href="/static/css/bulma-tooltip-1.0.4.min.css">
     <script defer src="/static/js/fontawesome-5.0.7.js"></script>
     <link rel="stylesheet" href="/static/css/style.css">
 </head>
@@ -72,6 +73,11 @@
                             </div>
                         </div>
                     </div>
+                    <div class="field tooltip is-tooltip-bottom is-tooltip-multiline" data-tooltip="Should this paste be accessible only with special URL and not shown in pastes list?">
+                        <label class="checkbox">
+                            <input type="checkbox" name="paste-private" id="paste-private"> Private paste with unique URL?
+                        </label>
+                    </div>
                     <div class="field">
                         <label for="paste-language">Language:</label>
                         <div class="control">