Fixed niche size/pages count during parsing redbubble's pages

Adapted to the changes on redbubble.com

added several more convenient variants to view search page's products
added ability to highlight niche tags type (evergreen, tailed, trending in history and so on)
added more visible for user button "buy us a coffee"
fixed excel file extension to be .xlsx

adapt shredbubble to the changes that redbubble has been made on its' website