Adds a button to steam db info near the add to cart button
Adds a link to https://steamdb.info/ page of given link to game pages on Steam store.
NOTE: if there is more than one buy button (game that has multiple versions, free demo, DLCs, OST, bundle, etc.) there is a button added near each, but they all lead to same page, the URL of history page is based on URL of the game and nothing else.
NOTE: compatible with my other script - https://greasyfork.org/en/scripts/452120-steam-price-history-button but I don't recommend this one, since data on Steam Price History often seems outdated by years, misses sales, and is missing many games. If you scroll to bottom of Steam DB, there is a price history chart too.
