disableactions support

This patch adds a config option to disable certain internal action commands of
DokuWiki's main dispatcher.

The options resendpasswd and openregister were removed because they can now set
through this new option.

The config plugin needs to be adjusted.

darcs-hash:20060702121622-7ad00-1e80e77bcfb0ae561fe7abd79cfbe1bb158be720.gz