[mod] drop obsolete searx.brand namespace

The usages of the searx.brand namespace has been removed, the searx.brand
namespace is now longer needed.

The searx.brand namespace was an interim solution which has been added in commit
9e53470b, see commit message there ...

    This patch is a first 'proof of concept'.  Later we can decide to remove the
    brand namespace entirely or not.

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>