[TYPO3-doc] Updated Document model

[Fabien Udriot]

Hi folks,

FYI, I have updated the Document Model while properly working on the implementation of the
rendering. For the time being, (some) changes are on a pending Git branch.

* Added the property "status". We (with Martin) faced the need for such a property enabling to store
status from the rendering. I went for a string field which enables human comprehensive message vs
numeric values which are hard to guess without referring to a guide.

* Added the property "origin". I am not totally happy with the name, I must say. I have other
suggestion such as "source" or "subtype". I would need to track the info where the package comes
from:  ter, git, svn because documents are going to be handled differently. We could also exploit
more the field "type" to make the distinguish but I am not convinced. Would you have an opinion?

* Following a suggestion from Robert, I have changed property "uri" and "locale" (old name was
language) to be handled as object since F3 1.1 is shipping an API. I have created a branch for
discussing the change / implementation if needed. You will notice I have added a few classes:

* Classes/Domain/Model/Uri.php extending \TYPO3\FLOW3\Http\Uri
* Classes/Domain/Model/Locale.php extending \TYPO3\FLOW3\I18n\Locale
* Classes/Domain/Repository/UriRepository.php enabling to query the URI repository.

The Git branch: https://github.com/typo3/TYPO3.Docs/commit/5ae448433c7fa7377dbfbe76e9bb938aa29724bf

Fabien