Link the credits in Special:Version in all languages

Link the credits in Special:Version in all languages

Add the link to {{SERVER}}{{SCRIPTPATH}}/CREDITS in Special:Version
in the code and not in the interface message, which is
way more straightforward, makes the message  easier and
assures that the developers are credited no matter of the current
interface language.

The following languages need interface changes after this is merged:
He, Ko, Bcl, Jv (the fact that this list is so short once again
proves the point that the link isn't set in many languages). I'll
take care of those.

Change-Id: If12c4eb8453da40ede4b9768b2dacfaf838aa2ab