New $lang parameters for an easier translation of the script

[Mickey]

Hello, Dody and Zubby

I'm adaptating the 5.3-5.4 script for new sites, and I found a bug.

The word "Category:" is in english in many html files of the templates.
It could be better to transform this word into new "$lang" lines included in the lang/english.php file

Here is the list of the files with "Category:"

kosmos/become_editor_form.html
kosmos/new_link_rows.html
kosmos/premium_rows.html
kosmos/rows.html
kosmos/sponsored_rows.html

blocks/block.new_and_updated_listing_rows.html
blocks/block.random_listing_rows.html
blocks/block.view_other_links_rows.html

2 other files with "Category:" are in the /cp folder, but most of the users don't translate the /cp files (it's a hard works for himself, not for the visitors)