[tools] Add link to v8.dev tools and margin fix

This CL adds a link to v8.dev/tools to direct
to all available versions of the tool. Also
fixes margin in between text and card div.

Bug: v8:10664

Change-Id: I8c0b137ffbdd88c4a41fd1ab8038985595056ada
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2315988Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Zeynep Cankara <zcankara@google.com>
Cr-Commit-Position: refs/heads/master@{#69031}

tools/index.html

@@ -53,11 +53,9 @@ a:hover, a:active {
 .card:hover {
   box-shadow: 0 8px 16px 0 rgba(0,0,0,0.2);
 }
-dd {
-  padding: 10px 10px 10px 10px;
-}
-dt {
+dd, dt {
   padding: 10px 10px 10px 10px;
+  margin: auto;
 }
 </style>
 </head>
@@ -106,6 +104,10 @@ dt {
             <dt><a href="./zone-stats/index.html">Zone Stats</a></dt>
             <dd>Analyse zone memory usage.</dd>
           </div>
+          <div class="card">
+            <dt><a href="https://v8.dev/tools">Other V8 Versions</a></dt>
+            <dd>Check out the V8 website for available tool versions.</dd>
+          </div>
           <div class="card">
             <dt><a href="https://v8.dev">V8.Dev</a></dt>
             <dd>Check out the V8 website for more information.</dd>