Move server-site documents from james/server repository to james/site/server repository

See proposal:

http://mail-archives.apache.org/mod_mbox/james-server-dev/200609.mbox/%3c31010369.16221158229780564.JavaMail.root@elysia.void.it%3e

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I would like to move the James menu (Overview, James FAQ, Mailing lists,
Wiki) and the Project menu (Bug Database, Source Code, TODO, not sure
about Changelog) and Useful RFCs out from the server source tree and
only keep pages found in the documentation menu inside each specific
james source tree.

This way we can keep james 2.2 and james 2.3 documentations live at the
same time in an easy way, then we could move to 2.3+2.4, then 2.4 and
3.0 and so on.
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