(bug 49285) ArticleFeedbackv5: Text is blurry due to use of CSS3 filter

Blurry texts: moved background imgs & CSS grayscale filter to :before
* top left feedback count (#articleFeedbackv5-showing-count-wrap span)
* top right feedback entry status (.articleFeedbackv5-<status>-marker)

Updated fallback png cog image

Bug: 49285
Change-Id: Ibbdaad24102fb9add1d8401dfbfd679259e1089e
Merge "(bug 49285) ArticleFeedbackv5: Text is blurry due to use of CSS3 filter"