hgweb: add tags links and manifest links
This adds a simple new tags page to browse by tag, adds the tag link
everywhere, and adds manifest links to the tags and changelog pages.
#header#
<title>#repo#: #file# annotate</title>
</head>
<body>
<div class="buttons">
<a href="?cmd=changelog;rev=#rev#">changelog</a>
<a href="?cmd=tags">tags</a>
<a href="?cmd=changeset;node=#node#">changeset</a>
<a href="?cmd=manifest;manifest=#manifest#;path=#path#">manifest</a>
<a href="?cmd=file;file=#file#;filenode=#filenode#">file</a>
<a href="?cmd=filelog;file=#file#;filenode=#filenode#">revisions</a>
</div>
<h2>Annotate #file# (#filenode#)</h2>
<table>
<tr>
<td class="metatag">changeset #rev#:</td>
<td><a href="?cmd=changeset;node=#node#">#node#</a></td></tr>
#parent1#
#parent2#
<tr>
<td class="metatag">manifest:</td>
<td><a href="?cmd=manifest;manifest=#manifest#;path=/">#manifest#</a></td></tr>
<tr>
<td class="metatag">author:</td>
<td>#author#</td></tr>
<tr>
<td class="metatag">date:</td>
<td>#date#</td></tr>
</table>
<br/>
<table cellspacing="0" cellpadding="0">
#annotate#
</table>
#footer#