Fixed #20307 -- Word repeated in tutorial.

Replaced "the the" in the tutorial with "the".
Fixed the reusable apps docs to use a rst file extension for the README and follow PEP8 a bit more.
Fixed a rST bug in the README template in the reusable apps docs.
Fix CharField typo in legacy-databases.txt docs

The example Person model in the legacy databases HowTo had a typo referring to ChaField instead of Charfield
Merge pull request #1029 from carmi/patch-1

Fix CharField typo in legacy-databases.txt docs
Updated Transifex links to the Django project

Translations for the Django framework are now hosted on the
django-core Transifex project, and the django project is only
dedicated to a team-only hub project.