hgwebdir: read --webdir-conf as actual configuration to ui (issue1586)
This cleans up code and allows specification of values more globally. For
example, it's now possible to specify web.contact in webdir-conf for all
repositories without a specified contact set.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<link rel="icon" href="#staticurl#hgicon.png" type="image/png">
<meta name="robots" content="index, nofollow" />
<link rel="stylesheet" href="#staticurl#style.css" type="text/css" />