Extension Localisation Wiki using Translate/Configuration

Once installed, a variety of configuration settings are altered to provide a more effective localisation environment.

Documentation language code
The extension provides an ability for a language code to be used for documenting messages, making it easier for translators and localisers who may not always understand a messages context. The message for this language will be updated by someone familiar with the extension, perhaps the extensions developer.

Dedicated translation namespace
To avoid conflicting between MediaWiki messages that are customized, and messages that are being Translated, a separate namespace is used for the translation of message.

This can be turned in to a function if more namespaces are desired.

Messages directory
Due to the nature of the extensions being localised, it makes sense to place them in a separate directory (rather than just put them with the rest of the extensions). They will instead be placed in the extensions/messages/ directory.

Disable MediaWiki message localisation
Since we do not have any interest in localising MediaWiki messages (this is all handlled by translatewiki.net anyway) all message groups should be disabled for now - more will be added later on.