Remove the multiple copies of the documentation

There are currently too many copies of the documentation laying around (even if with different purposes). This totally destroys the UX and makes docs difficult to find as they have a poor pagerank.

Docs are currently being hosted at the following URLs:

• doc.qt.digia.com (up to 4.7)
• qt-project.org/doc (4.7, 4.8, 5.0)
• doc-snapshot.qt-project.org (Qt 5 stable/dev branches, Qt 4's 4.8 branch)

There are also special versions such as "latest-snapshot" as well as "latest" / "stable" , which used to be symlinks to the not-released-yet and the last-released versions.

Moreover, we have a very poor redirection scheme in place: http://doc.qt.digia.com/4.8/qobject.html redirects on http://qt-project.org/doc/qt-4.8/ , losing the specific page URL. This causes broken links, as the docs themselves and many pages on the internet still link to

• http://doc.trolltech.com/4.x/foo.html
• http://doc.qt.nokia.com/4.x/foo.html

and now those get rewritten to digia.com/4.x/ which will make them land to generic pages.

Proposal:

1. DO NOT HOST ANY UP-TO-DATE DOCUMENTATION on http://doc.qt.digia.com/; depending on the URL's path, rewrite those urls as PERMANENTLY MOVED (HTTP 301, in order to bring some pagerank) with the right ones on qt-project.org/doc/. Do rewrite 4.7 in doc/qt-4.7/, 4.8 in doc/qt-4.8/, 5.0 on qt-project.org/doc/qt-5.0/, doc.qt.digia.com/ {stable,latest} to qt-project.org/doc/{stable,latest}
   1. Eventually, leave only pre-4.7 docs in order not to break any links (see below), but silence search engines via robots.txt
2. Add qt-project.org/doc/ {stable,latest}

   as a 302 redirect (not 301, the target will change), targeting the latest released Qt 5 version

3. Make the above points work with the old doc.trolltech.com and doc.qt.nokia.com (all in all, all that's needed is a trivial URL rewrite on those sides, so we might ask the favour...), as there are HUNDREDS of links (even in our own docs) out there pointing at those websites
4. Statically create a set of redirects for the modularized Qt 5.0, so that going to f.i. qt-project.org/doc/qt-5.0/qobject.html will rewrite the url (301) into qt-project.org/doc/qt-5.0/qtcore/qobject.html – that is, will add the module name. I expect very few conflicts in this phase. If there are any conflicts we should see a way to solve them (eventually, by renaming the pages, or creating intermediate landing pages for disambiguation)
5. Remove doc-snapshot.qt-project.org from search engines via robots.txt, eventually allowing it to index only the front page (end users are NOT expected to find results in there by googling)

(Edited: changed the above bullet list to a number list, so we can reference points)