doc: Update Japanese man pages translation

* sync current English man pages on master branch
* delete lxc-shutdown.sgml.in
* add lxc-snapshot.sgml.in
* update FSF address (same as 250b1eec71b074acdff1c5f6b5a1f0d7d2c20b77)
* remove trailing whitespaces in legacy/lxc-ls.sgml.in (same as 8900b9eb2514c07047541833286428572493a9fd)